Hydroxyaryl functionalized polymers

ABSTRACT

Vulcanizates with desirable properties can be obtained from compounds incorporating polymers that include hydroxyl group-containing aryl functionalities. The functionalities can be incorporated by using any or all of appropriate initiators, monomers and optional terminating compounds. Such polymers exhibit excellent interactivity with both conventional and non-conventional fillers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of U.S. application Ser. No. 14/523,903, which wasfiled 26 Oct. 2014 and issued as U.S. Pat. No. 10,227,425 on 12 Mar.2019, which is a continuation of U.S. application Ser. No. 12/810,846,which had a 371(c) completion (filing) date of 7 Jul. 2010 and nowissued as U.S. Pat. No. 8,871,871 on 28 Oct. 2014, which was a nationalstage entry of intl. appl. PCT/US2008/088384, filed 28 Dec. 2008, whichclaimed the benefit of each of U.S. provisional appl. Nos. 61/017,278filed 28 Dec. 2007, 61/127,586 filed 14 May 2008, 61/082,181 filed 18Jul. 2008, and 61/110,107 filed 31 Oct. 2008.

BACKGROUND INFORMATION

Traction performance is one of the primary evaluation criteria for tiretreads, and performance on wet surfaces such as snow and ice is animportant factor in that evaluation.

Deformation of tread rubber induced by road surface asperities, rate ofwater drainage between the tread and road surface, and possible adhesiveinteractions at the interface between tread and road are some of thecomplex, interrelated factors that complicate the type of quantitativemechanistic understanding needed to formulate tread compounds. Tofurther improve tire performance, those involved in tread design andmanufacture continue to investigate the numerous factors that affect wettraction.

Rubber goods such as tire treads are made from elastomeric compositionsthat contain one or more reinforcing materials; see, e.g., TheVanderbilt Rubber Handbook, 13th ed. (1990), pp. 603-04. The firstmaterial commonly used as a filler was carbon black, which imparts goodreinforcing properties and excellent wear resistance to rubbercompositions. However, carbon black-containing formulations often sufferfrom increased rolling resistance which correlates with an increase inhysteresis and heat build-up during operation of the tire, propertieswhich need to be minimized to increase motor vehicle fuel efficiency.

The increased hysteresis resulting from the use of carbon black can besomewhat counteracted by reducing the amount (i.e., volume) of and/orincreasing the particle size of the carbon black particles, but therisks of deterioration in reinforcing properties and wear resistancelimits the extent to which these routes can be pursued.

Over the last several decades, the use of amorphous silica and treatedvariants thereof, both alone and in combination with carbon black hasgrown significantly. Use of silica fillers can result in tires withreduced rolling resistance, increased traction on wet surfaces, andother enhanced properties.

Despite the outstanding performance of treads employing silica andcarbon black as reinforcing fillers, ever-more demanding regulatory andperformance demands have led to continued investigations of alternativefillers. Examples of such non-conventional fillers include aluminumhydroxide (see, e.g., U.S. Pat. Nos. 6,242,522 and 6,489,389 as well asH. Mouri et al., “Improved Tire Wet Traction Through the Use of MineralFillers,” Rubber Chem. and Tech., vol. 72, pp. 960-68 (1999)); metaloxides having very high densities (see U.S. Pat. No. 6,734,235);magnetizable particles such as iron oxide or strontium ferrite used inthe manufacture of tire sidewalls (see U.S. Pat. No. 6,476,110);macroscopic (e.g., 10-5000 μm mean diameter) particles of hard mineralssuch as alumina, CaCO₃, and quartz (see U.S. Pat. No. 5,066,702); pumicecontaining SiO₂ (U.S. Publ. No. 2004/0242750 A1); sub-micron ZnOparticles (see U.S. Pat. No. 6,972,307); and micron-scale ZnSO₄, BaSO₄and/or TiO₂ (see U.S. Pat. No. 6,852,785). More often, potentiallyuseful fillers are merely strung together in list format; see, e.g.,U.S. Pat. Nos. 4,255,296 and 4,468,496. Other non conventional fillermaterials include clays and complex oxides.

Recently, replacing some or all of the more common types of particulatefillers with inorganic oxides such as ferric oxide, ferrous oxide,aluminum oxide, etc., has been shown to provide vulcanizates withsuperior wet traction properties; see, e.g., U.S. Publ. No.2008/0161467).

Enhancing dispersion of reinforcing filler(s) throughout theelastomer(s) can improve processability and certain physical properties.Efforts in this regard include high temperature mixing in the presenceof selectively reactive promoters, surface oxidation of compoundingmaterials, surface grafting, and chemically modifying the polymer(s).

Chemical modification of polymers often occurs at a terminus. Terminalchemical modification can occur by reaction of a terminally active,i.e., living (i.e., anionically initiated) or pseudo-living, polymerwith a functional terminating agent. Terminal modification also can beprovided by means of a functional initiator, in isolation or incombination with functional termination. Functional initiators typicallyare organolithium compounds that additionally include otherfunctionality, typically functionality that includes a nitrogen atom.Unfortunately, functional initiators generally have relatively poorsolubility in hydrocarbon solvents of the type commonly used in anionicpolymerizations and cannot maintain propagation of living ends as wellas more common alkyllithium initiators such as butyllithium; bothcharacteristics negatively impact polymerization rate and efficiency.

Polymers incorporating 3,4-dihydroxyphenylalanine (DOPA) have beensynthesized for some time, often for adhesive applications; see, e.g.,U.S. Pat. No. 4,908,404. Because these polymers can be costly anddifficult to produce, so-called bulk polymers approximating theirperformance have been pursued; see Westwood et al., “Simplified PolymerMimics of Cross-Linking Adhesive Proteins,” Macromolecules 2007, 40,3960-64. However, the de-protection step utilized by the foregoingapproach cannot be used when the polymer contains ethylenicunsaturation.

SUMMARY

Vulcanizates with desirable properties can be obtained from compoundsemploying polymers that include hydroxyl group-containing arylfunctionalities. Such polymers enhance interactivity with bothconventional and non-conventional fillers.

In one aspect is provided a method of making a functional polymer thatincludes one or more types of polyene mer and at least onefunctionalizing unit which includes an aryl group having at least onedirectly bonded OR substituent where R is a hydrolyzable protectinggroup. In a solution that includes an initiating compound and one ormore types of ethylenically unsaturated monomers which include at leastone type of polyene, the initiating compound is allowed to anionicallyinitiate polymerization of the monomers so as to provide a carbanionicpolymer. Optionally, the carbanionic polymer can be reacted with aterminating compound. The functionalizing unit(s) result from (i.e.,is/are radical(s) of) at least one of the initiating compound, themonomer(s), and the optional terminating compound.

The method can include an additional reaction step in which theprotecting R group is hydrolyzed so as to provide an aryl group havingat least one directly bonded hydroxyl group. This additional step can bethe reaction of the carbanionic polymer with a terminating compound(s).

The aryl group of the functionalizing unit can include at least twodirectly bonded OR groups. Also or alternatively, a functionalizing unitcan include a second aryl group, particularly when the unit is derivedfrom a terminating compound.

Initiating compounds that can provide the functionalizing unit includethose having the general formulaR¹ZQ-M  (I)where M is an alkali metal atom; R¹ is a substituted or unsubstitutedaryl group having at least one OR² substituent group where each R² is anR group that also is nonreactive toward M; Z is a single bond or asubstituted or unsubstituted alkylene (acyclic or cyclic) or arylenegroup; and Q is a group bonded to M through a C, N or Sn atom. The R¹aryl group can include a single aromatic ring (phenyl group) or two ormore fused aromatic rings. Initiation with this type of functionalinitiator can result in a macromolecule that includes at least onepolymer chain having terminal functionality defined by the generalformula-Q′ZR³  (II)or a functionalized polymer defined by the general formulaκ-π-Q′ZR³  (III)where R³ is a substituted or unsubstituted aryl group that includes atleast one OR⁴ substituent group (with R⁴ being H or R); Z is defined asabove; Q′ is the radical of Q, i.e., the residue of an initiating moietybonded to the polymer chain through a C, N or Sn atom; π is a polymerchain; and K is a hydrogen atom or a functional group-containing radicalgenerated by reaction of the polymer with a terminating compound. Wheremore than one OR⁴ group is present, each can be on the same or differentrings and, in certain embodiments, at least two OR⁴ substituents can beadjacent.

Where a functionalizing unit results from a monomer, the monomer caninclude an aryl group, preferably a phenyl group, that has at least onedirectly bonded OR group. The resulting polymer can include multiple merresulting from incorporation of alkenes (A units) and at least three merof the type just described (B units) which can be non-adjacent or canconstitute a block within the polymer. If a block of B units is present,it can be relatively close to a terminus of the polymer, i.e., no morethan six, four or two polymer chain atoms from a terminal unit. In otherembodiments, one or more B units can be incorporated into the polymer,typically after polymerization of the other monomers has beenaccomplished, optionally followed by reaction with a compound whichoptionally can provide additional terminal functionality to the polymer.(This compound need not be of a type capable of providing the specificfunctionality shown below in formula (IV) and, instead, can provide anyof a variety of functionalities including inter alia those containingone or more heteroatoms.)

Where a functionalizing unit results from reaction of the carbanionicpolymer with a terminating compound, that functionality can have thegeneral formula

where Z′ is a single bond or an alkylene group; R³ is defined as above;R⁶ is H, a substituted or unsubstituted aryl group which optionally caninclude one or more OR⁴ substituent groups, R′, or JR′ where J is O, S,or —NR′ (with each R′ independently being a substituted or unsubstitutedalkyl group); and Q″ is the residue of a functionality that is reactivewith carbanionic polymers but which itself is non-reactive toward suchpolymers. The R³ aryl group can include a single aromatic ring (phenylgroup) or two or more fused aromatic rings, and the OR⁴ groups can be onthe same or different rings of the aryl group although, in certainembodiments, the OR⁴ substituents advantageously can be adjacent.Additionally, R⁶ and a portion of R³ can be linked so that, togetherwith one or more atoms of the Q″ group to which they are bonded (andoptionally Z′), they form a ring that is bound to or fused with the R³aryl group; examples include any of a variety of flavone- andanthrone-type structures which have one or more OR⁴ substituent groupson at least one of the aryl groups. (This is described in more detailbelow in connection with formula (IVb).)

In a variation of the foregoing method, a similar functionalizing unitcan result from reaction of a terminating compound of the type justdescribed with other types of terminally reactive polymers, for example,a pseudo living polymer.

In certain embodiments, the polyene(s) can be conjugated dienes. Inthese and other embodiments, the polymer also can include vinyl aromaticmer which preferably are incorporated substantially randomly with theconjugated diene mer along the polymer chain.

In each of the foregoing, the polymer can be substantially linear. Incertain embodiments, the substantially linear polymer can include as aterminal moiety the radical of a compound that includes at least onearyl group having one or more substituent groups that can be hydrolyzedto hydroxyl groups.

Compositions that include particulate fillers and polymers of the typedescribed above also are provided, as are methods of providing and usingsuch compositions. Also provided are vulcanizates made from such filledcompositions. In any or all, the polymer can interact with particulatefillers including carbon black and silica as well as, advantageously,non-conventional fillers such as inorganic oxides and hydroxides, claysand the like.

Other aspects of the present invention will be apparent to theordinarily skilled artisan from the description of various embodimentsthat follows. In that description, the following definitions applythroughout unless the surrounding text explicitly indicates a contraryintention:

-   -   “polymer” means the polymerization product of one or more        monomers and is inclusive of homo-, co-, ter-, tetra-polymers,        etc.;    -   “mer” or “mer unit” means that portion of a polymer derived from        a single reactant molecule (e.g., ethylene mer has the general        formula —CH₂CH₂—);    -   “copolymer” means a polymer that includes mer units derived from        two reactants, typically monomers, and is inclusive of random,        block, segmented, graft, etc., copolymers;    -   “interpolymer” means a polymer that includes mer units derived        from at least two reactants, typically monomers, and is        inclusive of copolymers, terpolymers, tetra-polymers, and the        like;    -   “random interpolymer” means an interpolymer having mer units        derived from each type of constituent monomer incorporated in an        essentially non-repeating manner and being substantially free of        blocks, i.e., segments of three or more of the same mer;    -   “reactive polymer” means a polymer having at least one site        which, because of the presence of an associated catalyst or        initiator, readily reacts with other molecules, with the term        being inclusive of inter alia pseudo-living and carbanionic        polymers;    -   “catalyst composition” is a general term encompasses a simple        mixture of ingredients, a complex of various ingredients that is        caused by physical or chemical forces of attraction, a chemical        reaction product of some or all of the ingredients, or a        combination of the foregoing, the result of which is a        composition displaying catalytic activity with respect to one or        more monomers of the appropriate type;    -   “gum Mooney viscosity” is the Mooney viscosity of an uncured        polymer prior to addition of any filler(s);    -   “compound Mooney viscosity” is the Mooney viscosity of a        composition that includes, inter alia, an uncured or partially        cured polymer and particulate filler(s);    -   “substituted” means containing a heteroatom or functionality        (e.g., hydrocarbyl group) that does not interfere with the        intended purpose of the group in question;    -   “directly bonded” means covalently attached with no intervening        atoms or groups;    -   “polyene” means a molecule with at least two double bonds        located in the longest portion or chain thereof, and        specifically is inclusive of dienes, trienes, and the like;    -   “polydiene” means a polymer that includes mer units from one or        more dienes;    -   “phr” means parts by weight (pbw) per 100 pbw rubber;    -   “non-coordinating anion” means a sterically bulky anion that        does not form coordinate bonds with the active center of a        catalyst system due to steric hindrance;    -   “non-coordinating anion precursor” means a compound that is able        to form a non-coordinating anion under reaction conditions;    -   “radical” means the portion of a molecule that remains after        reacting with another molecule, regardless of whether any atoms        are gained or lost as a result of the reaction;    -   “aryl group” means a phenyl group or a polycyclic aromatic        radical;    -   “terminus” means an end of a polymeric chain; and    -   “terminal moiety” means a group or functionality located at a        terminus.

Throughout this document, all values given in the form of percentagesare weight percentages unless the surrounding text explicitly indicatesa contrary intention. The relevant portions of any mentioned patent orpatent publication is incorporated herein by reference.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As apparent from the foregoing Summary, the method can involve any of avariety of possible permutations or combinations thereof, and theresulting polymer can be characterized in a variety of ways. Generally,the polymer includes mer derived from one or more polyenes, particularlydienes, and terminal functionality defined by either or both of formulas(II) and (IV) and/or one or more of the aforedescribed B mer units. Inat least certain embodiments, the polymer also can include directlybonded pendent aromatic groups.

The following describes the production and use of a polymer thatincludes multiple A mer, i.e., alkene units; optionally, multiple C mer,i.e., units that include a pendent aryl group, particularly a phenylgroup, and, where at least some of the desired functionalization is tobe derived from functional monomers, at least one B mer, i.e., a unitthat includes a pendent aryl, preferably phenyl, group with at least onedirectly bonded OR group. Each of the A, B and C mer can result fromincorporation of ethylenically unsaturated monomers.

The A mer typically result from incorporation of polyenes, particularlytrienes (e.g., myrcene) and dienes, particularly C₄-C₁₂ dienes and evenmore particularly conjugated dienes such as 1,3-butadiene,1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene,2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene,isoprene, 4-methyl-1,3-pentadiene, 2,4-hexadiene, and the like. Some orall of the A mer can be derived from one or more types of dienes,particularly one or more types of conjugated dienes, e.g.,1,3-butadiene. In some embodiments, essentially all (i.e., at least 95%)of the polyenes can be dienes, particularly conjugated dienes.

Polyenes can incorporate into polymeric chains in more than one way.Especially for tire tread applications, controlling this manner ofincorporation can be desirable. A polymer chain with an overall1,2-microstructure, given as a numerical percentage based on totalnumber of polyene units, of from ˜10 to ˜80%, optionally from ˜25 to˜65%, can be desirable for certain end use applications. A polymer thathas an overall 1,2-microstructure of no more than ˜50%, preferably nomore than ˜45%, more preferably no more than ˜40%, even more preferablyno more than ˜35%, and most preferably no more than ˜30%, based on totalpolyene content, is considered to be substantially linear. For certainend use applications, keeping the content of 1,2-linkages even lower,e.g., to less than about 7%, less than 5%, less than 2%, or less than1%, can be desirable.

Depending on the intended end use, one or more of the polymer chains caninclude pendent aromatic groups, which can be provided by C mer, i.e.,mer derived from vinyl aromatics, particularly the C₈-C₂₀ vinylaromatics such as, e.g., styrene, α-methyl styrene, p-methyl styrene,the vinyl toluenes, and the vinyl naphthalenes. When used in conjunctionwith one or more polyenes, C mer can constitute from ˜1 to ˜50%, from˜10 to ˜45%, or from ˜20 to ˜40% of the polymer chain; randommicrostructure can provide particular benefit in some end useapplications such as, e.g., rubber compositions used in the manufactureof tire treads. Where a block interpolymer is desired, C units canconstitute from ˜1 to ˜90%, generally from ˜2 to ˜80%, commonly from ˜3to ˜75%, and typically ˜5 to ˜70% of the polymer chain. (In thisparagraph, all percentages are mole percentages.)

Exemplary interpolymers include those in which one or more conjugateddienes are used to provide the A units, i.e., polydienes; among these,1,3-butadiene can be one of several or the only polydiene employed.Where C units are desired, they can be provided from styrene so as toprovide, for example, SBR. In each of the foregoing types of exemplaryinterpolymers, one or more B units also can be incorporated.

B units include a pendent aryl group which includes one or more directlybonded hydroxyl groups. Because the H atoms of hydroxyl groups areactive and can interfere with certain polymerization processes, the oneor more B units typically are provided from compounds that include Rgroups, i.e., groups that are non-reactive in the types of conditionsutilized when polymerizing ethylenically unsaturated monomers but whichlater can be removed, typically by hydrolysis or similar reaction, so asto provide the desired hydroxyl groups. The particular type(s) ofprotecting group(s) employed should not interfere with thepolymerization process, and the de-protection process employed toprovide hydroxyl groups should not destroy or otherwise react withethylenic unsaturation in the polymer resulting from the presence of Aunits. A non-limiting class of useful protecting groups istrialkylsiloxy groups, which can be provided by reacting hydroxyl groupswith a trialkylsilyl halide. While the following examples employtert-butyldimethylsiloxyl groups, others such as acetal, tert-butylether, 2-methoxyethoxy ether, and the like also can be used.

The number of OR groups on the aryl, typically phenyl, group of each Bunit need not be the same, where the number is the same, the OR groupsneed not be at the same position(s) on those rings. Using a phenyl groupas a representative aryl group, relative to the point of attachment ofthe phenyl group to the polymer chain, a single OR group can be locatedortho, meta, or para on the phenyl ring, while multiple OR groups can beprovided 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-, 3,6-, 2,3,4-, 2,3,5-, etc.,on the phenyl ring.

B units typically are provided from vinyl aromatic compounds thatinclude one or more hydroxyl-producing groups directly attached to theiraryl, typically phenyl, rings. Such compounds can be represented by thegeneral formulaCH₂═CHR¹  (V)where R¹ is defined as above and which here can include from 1 to 5inclusive OR groups with each R independently being the type ofprotecting group described above. (Although each R need not beidentical, ease and simplicity typically result in a single type of Rmoiety being used in a given compound.) The OR groups can besubstituents of the same ring of R¹ or can be substituents of differentrings and, where R¹ contains three or more OR groups, two of them can besubstituents of one ring with the other(s) being substituent(s) of otherring(s). In one embodiment, two OR groups can be at the 3 and 4positions of the same ring within the aryl group, preferably a phenylgroup. Where R¹ is other than a phenyl group and includes more than oneOR group and where the OR groups are on more than one ring, at least twoof the OR groups preferably are least somewhat proximate, i.e., directlybonded to ring C atoms that are separated by no more than 4, preferably3, and even more preferably 2, other ring atoms. Many of these compoundsadvantageously are soluble in the types of organic solvents set forthbelow.

When one or more formula (V)-type compounds is polymerized, it/theyprovide the B unit(s), after which each of the R moieties can behydrolyzed so as to provide phenolic hydroxyl groups.

The number of B units typically is small relative to the number of Aunits and, if present, C units; a relatively small number of B units hasbeen found to provide a satisfactory level of desired properties, withfurther improvements in those properties not necessarily beingproportional to the number of B units present. This relatively smallnumber can be expressed in a number of ways. For example, the weightpercentage of the final polymer attributable to B units commonly is lessthan 2%, more commonly from ˜0.1 to ˜1.5%, and typically from ˜0.2 to˜1.0%. The percentage of B mer relative to the total number of mer inthe polymer commonly is less than 1%, more commonly from ˜0.01 to˜0.75%, and typically from ˜0.05 to ˜0.5%. The total number of B unitsin a given polymer generally is from 1 to several dozen, commonly from 1to 12, more commonly from 1 to 10, and most commonly from 1 to 5.

The B units can be separated from one another, or two or more B unitscan be contiguous along the polymer chain. (While the ordinarily skilledartisan understands how to synthesize random and block interpolymers,each is discussed in some detail below.) Further, the B units canincorporated near the beginning of the polymerization, near the end ofthe polymerization, or at any one or more intermediate points; in thefirst two of the foregoing possibilities, a B unit can be providedwithin 6 chain atoms of, within 2 units of, adjacent to a terminus ofthe polymer, or as a terminal unit, either alone or as part of a block.

The foregoing types of polymers can be made by emulsion polymerizationor solution polymerization, with the latter affording greater controlwith respect to such properties as randomness, microstructure, etc.Solution polymerizations have been performed for many decades, so thegeneral aspects thereof are known to the ordinarily skilled artisan, soonly certain general aspects are provided here for convenience ofreference.

Both polar solvents, such as THF, and non-polar solvents can be employedin solution polymerizations, with the latter type being more common inindustrial practice. Examples of non-polar solvents include variousC₅-C₁₂ cyclic and acyclic alkanes as well as their alkylatedderivatives, certain liquid aromatic compounds, and mixtures thereof.The ordinarily skilled artisan is aware of other useful solvent optionsand combinations.

Depending on the nature of the polymer desired, the particularconditions of the solution polymerization can vary significantly. In thediscussion that follows, living polymerizations are described firstfollowed by a description of pseudo-living polymerizations. After thesedescriptions, optional functionalization and processing of polymers somade are discussed.

Solution polymerization typically involves an initiator. Exemplaryinitiators include organolithium compounds, particularly alkyllithiumcompounds. Examples of organolithium initiators includeN-lithio-hexamethyleneimine; n-butyllithium; tributyltin lithium;dialkylamino-lithium compounds such as dimethylaminolithium,diethylaminolithium, dipropylaminolithium, dibutylaminolithium and thelike; dialkylaminoalkyllithium compounds such asdiethylamino-propyllithium; and those trialkyl stanyl lithium compoundsinvolving C₁-C₁₂, preferably C₁-C₄, alkyl groups.

Multifunctional initiators, i.e., initiators capable of forming polymerswith more than one living end, also can be used. Examples ofmultifunctional initiators include, but are not limited to,1,4-dilithiobutane, 1,10-dilithiodecane, 1,20-dilithioeicosane,1,4-dilithiobenzene, 1,4-dilithionaphthalene, 1,10-dilithioanthracene,1,2-dilithio-1,2-diphenylethane, 1,3,5-trilithio-pentane,1,5,15-trilithioeicosane, 1,3,5-trilithiocyclohexane,1,3,5,8-tetralithiodecane, 1,5,10,20-tetralithioeicosane,1,2,4,6-tetralithiocyclohexane, and 4,4′-dilithiobiphenyl.

In addition to organolithium initiators, so-called functionalizedinitiators also can be useful. These become incorporated into thepolymer chain, thus providing a functional group at the initiated end ofthe chain. Examples of such materials include lithiated aryl thioacetals(see, e.g., U.S. Pat. No. 7,153,919) and the reaction products oforganolithium compounds and, for example, N-containing organic compoundssuch as substituted aldimines, ketimines, secondary amines, etc.,optionally pre-reacted with a compound such as diisopropenyl benzene(see, e.g., U.S. Pat. Nos. 5,153,159 and 5,567,815). Use of a Natom-containing initiator such as, for example, lithiated HMI, canfurther enhance interactivity between the polymer chains and carbonblack particles. Many of these functional initiators are poorly solublein many of the solvents set forth above, particularly those solventsthat are relatively non-polar.

In contradistinction, many compounds included in formula (I) exhibitacceptable solubility in the types of organic liquids commonly employedas solvents in solution polymerizations. Compounds included within thisformula hereinafter are referred to as R¹-containing initiators.

The aryl group of the R¹-containing initiator can be a phenyl group ortwo or more fused aromatic rings. Where the R¹ aryl group includes morethan one OR² group (with each R² being an R group that is nonreactivetoward M), the OR² groups can be substituents of the same ring or ofdifferent rings within the aryl group; where the aryl group containsthree or more OR² groups, two of them can be substituents of one ringwith the other(s) being substituent(s) of other ring(s). In oneembodiment, two OR² groups can be at the 3 and 4 positions of the samering within the aryl group, preferably a phenyl group. Where R¹ is otherthan a phenyl group and includes more than one OR² group and where theOR² groups are on more than one ring, at least two of the OR² groupspreferably are at least somewhat proximate, i.e., directly bonded toring C atoms that are separated by no more than 4, preferably 3, andeven more preferably 2, other ring atoms. Where a single OR² group ispresent on a phenyl group, it can be located at any ring position,although para from Z might be preferable for certain applications.

The R² moieties of the R¹-containing initiator ensure that no activehydrogen atoms are present in the R¹ aryl group. Such active hydrogenatoms would interfere with the ability of the R¹-containing initiator toanionically initiate polymerizations. Unless a particular R² moietyconstitutes a group that is capable of providing interactivity withparticulate filler, it preferably also is capable of being hydrolyzed toa hydrogen atom. Trialkylsiloxy groups are a non-limiting example of thetype of group that can serve these dual purposes; such groups can beprovided by reacting hydroxyl groups attached to the R¹ aryl group witha trialkylsilyl halide. Although each R² need not be identical, ease andsimplicity typically result in a single type of R² moiety for a givenR¹-containing initiator.

When the R¹-containing initiator initiates polymerization, its radicalforms one end of a polymer chain (see formulas (II) and (III)). The R²moieties of this radical typically are hydrolyzed so as to providehydroxyl substituents to the R³ group of formulas (II) and (III). Thistype of R³ group has been found to provide excellent interactivity witha wide variety of particulate fillers including carbon black and silicaas well as non-conventional fillers such as inorganic oxides andhydroxides, clays and the like.

In the R¹-containing initiator, M is an alkali metal atom (preferably aK, Na or Li atom, most preferably a Li atom), and Q is a group bonded toM through a C, N or Sn atom. Generally, Q does not contain any activehydrogen atoms which, as appreciated by the ordinarily skilled artisan,interfere with the efficacy of the R¹-containing initiator. Potentiallyuseful Q groups are too numerous for a comprehensive listing, but a fewnon-limiting examples can be provided; from these, the ordinarilyskilled artisan can envision numerous other alternatives.

Thioacetals are one type of potentially useful Q group. Thesefunctionalities have the general formula

where R¹⁵ is a C₂-C₁₀ alkylene group, preferably a C₂-C₈ alkylene group,more preferably a C₃-C₆ group; X is selected from S, O and NR¹⁶ whereinR¹⁶ can be a C₁-C₆ trialkylsilyl group, a C₁-C₂₀ alkyl group, a C₄-C₂₀cycloalkyl group, a C₆-C₂₀ aryl group with the proviso that any of thefollowing can be attached: C₁-C₁₀ alkyl groups, C₆-C₂₀ aryl groups,C₂-C₁₀ alkenyl groups, C₃-C₁₀ non-terminal alkynyl groups, ethers,tert-amines, phosphines, sulfides, silyls, and mixtures thereof. Onepreferred species includes an S atom as X and a C₃ alkylene group asR¹⁵, i.e., a 1,3-dithiane. In certain aspects, Q can be a group thatincludes a heteroatom-substituted cyclic moiety adapted to bond to analkali metal atom, such as Li. For additional information, theinterested reader is directed to U.S. Pat. No. 7,153,919.

Other potentially useful Q groups include SnR⁷ ₂ where each R¹independently is a hydrocarbyl (e.g., alkyl, cycloalkyl, aryl, aralkyl,alkaryl, etc.) group or, together, form a cycloalkyl group, and NR⁸where R⁸ is a hydrocarbyl group, particularly an aryl, a C₃-C₈cycloalkyl, or a C₁-C₂₀ alkyl group; included among the latter arecycloalkyleneiminoalkyllithium compounds such as those described in, forexample, U.S. Pat. No. 5,574,109. Also potentially useful as Q groupsare any of a variety of linear or branched alkyl groups, non-limitingexamples of which include butyl, pentyl, hexyl, heptyl, octyl, etc. Allthe foregoing initiators can be prepared from hydroxyl-substitutedbenzaldehydes through synthesis techniques described in more detail inthe examples that follow.

Compounds defined by formula (I) can be provided in a variety of ways,with the choice of synthetic route depending to a large extent onparticular nature of Q. For example, a compound with multiple hydroxylgroups attached to an aryl group and at least one other functionalitycan react, through the other functionality, with a compound so as toprovide a Q group; thereafter, the H atom(s) of the hydroxyl group(s)can be reacted with a compound that can provide the aforementioned R²groups, and the resulting material can be reacted with an alkalimetal-containing material, e.g., an organolithium. This type ofsynthetic approach is employed below in the examples to provide anexemplary dithiane-type initiator.

The R¹-containing initiator can be made external to the polymerizationvessel where it is to act as an initiator. In this case, a blend ofmonomer(s) and solvent can be charged to the reaction vessel, followedby addition of initiator, which often is added as part of a solution orblend (i.e., in a solvent carrier). For reasons of convenience, theR¹-containing initiator typically is synthesized in situ.

Although the ordinarily skilled artisan understands the conditionstypically employed in solution polymerization, a representativedescription is provided for ease of reference. The following is based ona batch process, although the ordinarily skilled artisan can adapt thisdescription to, semi-batch, continuous, or other processes.

Solution polymerization typically begins by charging a blend ofmonomer(s) and solvent to a suitable reaction vessel, followed byaddition of a coordinator (if used) and initiator, which often are addedas part of a solution or blend; alternatively, monomer(s) andcoordinator can be added to the initiator. Both randomization and vinylcontent (i.e., 1,2-microstructure) can be increased through inclusion ofa coordinator, usually a polar compound. Up to 90 or more equivalents ofcoordinator can be used per equivalent of initiator, with the amountdepending on, for example, the amount of vinyl content desired, thelevel of non-polyene monomer employed, the reaction temperature, andnature of the specific coordinator employed. Compounds useful ascoordinators include organic compounds that include a heteroatom havinga non-bonded pair of electrons (e.g., O or N). Examples include dialkylethers of mono- and oligo-alkylene glycols; crown ethers; tertiaryamines such as tetramethylethylene diamine; THF; THF oligomers; linearand cyclic oligomeric oxolanyl alkanes (see, e.g., U.S. Pat. No.4,429,091) such as 2,2′-di(tetrahydrofuryl) propane, di-piperidylethane, hexamethylphosphoramide, N,N′-dimethylpiperazine,diazabicyclooctane, diethyl ether, tributylamine, and the like.

Typically, a solution of polymerization solvent(s) and the monomer(s) isprovided at a temperature of from about −80° to +100° C., more commonlyfrom about −40° to +50° C., and typically from ˜0° to +30° C.; to thissolution is added an initiating compound or, where a functionalizingunit is to be provided from the initiator, and the R¹-containinginitiator (or its precursor with an organolithium, typically analkyllithium). The solution can have a temperature of from about −70° to˜150° C., more commonly from about −20° to ˜120° C., and typically from˜10° to ˜100° C. The polymerization is allowed to proceed underanhydrous, anaerobic conditions for a period of time sufficient toresult in the formation of the desired polymer, usually from ˜0.01 to˜100 hours, more commonly from ˜0.08 to ˜48 hours, and typically from˜0.15 to ˜2 hours. After a desired degree of conversion has beenreached, the heat source (if used) can be removed and, if the reactionvessel is to be reserved solely for polymerizations, the reactionmixture is removed to a post-polymerization vessel for functionalizationand/or quenching.

Polymers made according to anionic techniques generally have a numberaverage molecular weight (M_(n)) of up to 500,000 Daltons. In certainembodiments, the M_(n) can be as low as ˜2000 Daltons; in these and/orother embodiments, the M_(n) advantageously can be at least ˜10,000Daltons or can range from ˜50,000 to ˜250,000 Daltons or from ˜75,000 to˜150,000 Daltons. Often, the M_(n) is such that a quenched sampleexhibits a gum Mooney viscosity (ML₄/100° C.) of from ˜2 to ˜150, morecommonly from ˜2.5 to ˜125, even more commonly from ˜5 to ˜100, and mostcommonly from ˜10 to ˜75.

Certain end use applications call for polymers that have properties thatcan be difficult or inefficient to achieve via anionic (living)polymerizations. For example, in some applications, conjugated dienepolymers having high cis-1,4-linkage contents can be desirable.Polydienes can be prepared by processes using catalysts (as opposed tothe initiators employed in living polymerizations) and may displaypseudo-living characteristics.

Certain types of catalyst systems are known to be useful in producingvery stereospecific 1,4-polydienes from conjugated diene monomers. Somecatalyst systems preferentially result in cis-1,4-polydienes, whileothers preferentially provide trans-1,4-polydienes, and the ordinarilyskilled artisan is familiar with examples of each type. The followingdescription is based on a particular cis-specific catalyst system,although this merely is for sake of exemplification and is notconsidered to be limiting to the functionalizing method and compounds.

Exemplary catalyst systems can employ lanthanide metals which are knownto be useful for polymerizing conjugated diene monomers. Specifically,catalyst systems that include a lanthanide compound can be used toprovide cis-1,4-polydienes from one or more types of conjugated dienes.Preferred lanthanide-based catalyst compositions include those describedin U.S. Pat. No. 6,699,813 and patent documents cited therein. Acondensed description is provided here for convenience and ease ofreference.

Exemplary lanthanide catalyst compositions include (a) a lanthanidecompound, an alkylating agent and a halogen-containing compound(although use of a halogen-containing compound is optional when thelanthanide compound and/or the alkylating agent contains a halogenatom); (b) a lanthanide compound and an aluminoxane; or (c) a lanthanidecompound, an alkylating agent, and a non-coordinating anion or precursorthereof.

Various lanthanide compounds or mixtures thereof can be employed, withpreference given to those which are soluble in aromatic, aliphatic,and/or cycloaliphatic liquids, although hydrocarbon-insoluble lanthanidecompounds can be suspended in the polymerization medium. Preferredlanthanide compounds include those which include at least one Nd, La, orSm atom or those including didymium. The lanthanide atom(s) in thelanthanide compounds can be in any of a number of oxidation states,although the +3 oxidation state is most common. Exemplary lanthanidecompounds include carboxylates, organophosphates, organophosphonates,organophosphinates, xanthates, carbamates, dithiocarbamates,β-diketonates, alkoxides, aryloxides, halides, pseudo-halides,oxyhalides, etc.

Typically, the lanthanide compound is used in conjunction with one ormore alkylating agents, i.e., organometallic compounds that can transferhydrocarbyl groups to another metal. These agents typically areorganometallic compounds of electropositive metals such as Groups 1, 2,and 3 metals. Exemplary alkylating agents include organoaluminumcompounds and organomagnesium compounds. The former include (1)compounds having the general formula AlR⁹ _(n)X_(3-n)′ where n is aninteger of from 1 to 3 inclusive, each R⁹ independently is a monovalentorganic group (which may contain heteroatoms such as N, O, B, Si, S, P,and the like) connected to the Al atom via a C atom and each X′independently is a hydrogen atom, a halogen atom, a carboxylate group,an alkoxide group, or an aryloxide group; and (2) oligomeric linear orcyclic aluminoxanes, which can be made by reactingtrihydrocarbylaluminum compounds with water. The latter includecompounds having the general formula MgR¹⁰ _(y)X_(2-y)′ where X′ isdefined as above, y is an integer of from 1 to 2 inclusive, and R¹⁰ isthe same as R⁹ except that each monovalent organic group is connected tothe Mg atom via a C atom.

Some catalyst compositions contain compounds with one or more labilehalogen atoms. Useful halogen-containing compounds include elementalhalogens, mixed halogens, hydrogen halides, organic halides, inorganichalides, metallic halides, organometallic halides, and mixtures thereof.The halogen-containing compounds preferably are soluble in solvents suchas those described above with respect to lanthanide compounds, althoughhydrocarbon-insoluble compounds can be suspended in the polymerizationmedium.

Other catalyst compositions contain a non-coordinating anion or anon-coordinating anion precursor. Exemplary non-coordinating anionsinclude tetraarylborate anions, particularly fluorinated tetraarylborateanions, and ionic compounds containing non-coordinating anions and acountercation (e.g., triphenylcarboniumtetrakis(pentafluorophenyl)borate). Exemplary non-coordinating anionprecursors include boron compounds that include strongelectron-withdrawing groups.

Catalyst compositions of this type have very high catalytic activity forpolymerizing conjugated dienes into stereospecific polydienes over awide range of concentrations and ratios, although polymers having themost desirable properties typically are obtained from systems thatemploy a relatively narrow range of concentrations and ratios ofingredients. Further, the catalyst ingredients are believed to interactto form an active catalyst species, so the optimum concentration for anyone ingredient can depend on the concentrations of the otheringredients. The following molar ratios are considered to be relativelyexemplary for a variety of different systems based on the foregoingingredients:

-   -   alkylating agent to lanthanide compound (alkylating agent/Ln):        from ˜1:1 to ˜200:1, preferably from ˜2:1 to ˜100:1, more        preferably from ˜5:1 to ˜50:1;    -   halogen-containing compound to lanthanide compound (halogen        atom/Ln): from ˜1:2 to ˜20:1, preferably from ˜1:1 to ˜10:1,        more preferably from ˜2:1 to ˜6:1;    -   aluminoxane to lanthanide compound, specifically equivalents of        aluminum atoms on the aluminoxane to equivalents of lanthanide        atoms in the lanthanide compound (Al/Ln): from ˜10:1 to        ˜50,000:1, preferably from ˜75:1 to ˜30,000:1, more preferably        from ˜100:1 to ˜1,000:1; and    -   non-coordinating anion or precursor to lanthanide compound        (An/Ln): from ˜1:2 to ˜20:1, preferably from ˜3:4 to ˜10:1, more        preferably from ˜1:1 to ˜6:1.

The molecular weight of polydienes produced with lanthanide-basedcatalysts can be controlled by adjusting the amount of catalyst and/orthe amounts of co-catalyst concentrations within the catalyst system. Ingeneral, increasing the catalyst and co-catalyst concentrations reducesthe molecular weight of resulting polydienes, although very lowmolecular weight polydienes (e.g., liquid polydienes) require extremelyhigh catalyst concentrations which necessitates removal of catalystresidues from the polymer to avoid adverse effects such as retardationof the sulfur cure rate. Including one or more Ni-containing compoundsto lanthanide-based catalyst compositions advantageously permits easyregulation of the molecular weight of the resulting polydiene withoutsignificant negative effects on catalyst activity and polymermicrostructure. Various Ni-containing compounds or mixtures thereof canbe employed, with preference given to those which are soluble inhydrocarbon solvents such as those set forth above.

The Ni atom in the Ni-containing compounds can be in any of a number ofoxidation states, although divalent Ni compounds, where the Ni atom isin the +2 oxidation state, generally are preferred. Exemplary Nicompounds include carboxylates, organophosphates, organophosphonates,organophosphinates, xanthates, carbamates, dithiocarbamates,β-diketonates, alkoxides, aryloxides, halides, pseudo-halides,oxyhalides, organonickel compounds (i.e., compounds containing at leastone C—Ni bond such as, for example, nickelocene, decamethyl-nickelocene,etc.), and the like.

The molar ratio of the Ni-containing compound to the lanthanide compound(Ni/Ln) generally ranges from ˜1:1000 to ˜1:1, preferably from ˜1:200 to˜1:2, and more preferably from ˜1:100 to ˜1:5.

These types of catalyst compositions can be formed using any of thefollowing methods:

-   -   (1) In situ. The catalyst ingredients are added to a solution        containing monomer and solvent (or simply bulk monomer). The        addition can occur in a stepwise or simultaneous manner. In the        case of the latter, the alkylating agent preferably is added        first followed by, in order, the lanthanide compound, the        nickel-containing compound (if used), and (if used) the        halogen-containing compound or the non-coordinating anion or        non-coordinating anion precursor.    -   (2) Pre-mixed. The ingredients can be mixed outside the        polymerization system, generally at a temperature of from about        −20° to about 80° C., before being introduced to the conjugated        diene monomer(s).    -   (3) Pre-formed in the presence of monomer(s). The catalyst        ingredients are mixed in the presence of a small amount of        conjugated diene monomer(s) at a temperature of from about −20°        to ˜80° C. The amount of conjugated diene monomer can range from        ˜1 to ˜500 moles, preferably from ˜5 to ˜250 moles, and more        preferably from ˜10 to ˜100 moles, per mole of the lanthanide        compound. The resulting catalyst composition is added to the        remainder of the conjugated diene monomer(s) to be polymerized.    -   (4) Two-stage procedure.        -   (a) The alkylating agent is combined with the lanthanide            compound in the absence of conjugated diene monomer, or in            the presence of a small amount of conjugated diene monomer,            at a temperature of from about −20° to ˜80° C.        -   (b) The foregoing mixture and the remaining components are            charged in either a stepwise or simultaneous manner to the            remainder of the conjugated diene monomer(s) to be            polymerized.        -   (The Ni-containing compound, if used, can be included in            either stage.)            When a solution of one or more of the catalyst ingredients            is prepared outside the polymerization system in the            foregoing methods, an organic solvent or carrier is            preferably employed. Useful organic solvents include those            mentioned previously.

The production of cis-1,4-polydiene is accomplished by polymerizingconjugated diene monomer in the presence of a catalytically effectiveamount of a catalyst composition. The total catalyst concentration to beemployed in the polymerization mass depends on the interplay of variousfactors such as the purity of the ingredients, the polymerizationtemperature, the polymerization rate and conversion desired, themolecular weight desired, and many other factors; accordingly, aspecific total catalyst concentration cannot be definitively set forthexcept to say that catalytically effective amounts of the respectivecatalyst ingredients should be used. The amount of the lanthanidecompound used generally ranges from ˜0.01 to ˜2 mmol, preferably from˜0.02 to ˜1 mmol, and more preferably from ˜0.03 to ˜0.5 mmol per 100 gconjugated diene monomer. All other ingredients generally are added inamounts that are based on the amount of lanthanide compound (see thevarious ratios set forth previously).

Polymerization preferably is carried out in an organic solvent, i.e., asa solution or precipitation polymerization where the monomer is in acondensed phase. The catalyst ingredients preferably are solubilized orsuspended within the organic liquid. The amount (wt. %) of monomerpresent in the polymerization medium at the beginning of thepolymerization generally ranges from ˜3 to ˜80%, preferably ˜5 to ˜50%,and more preferably ˜10% to ˜30%. (Polymerization also can be carriedout by means of bulk polymerization conducted either in a condensedliquid phase or in a gas phase.)

Regardless of whether a batch, continuous, or semi-continuous process isemployed, the polymerization preferably is conducted with moderate tovigorous agitation under anaerobic conditions provided by an inertprotective gas. The polymerization temperature may vary widely, althoughtypically a temperature of from ˜20° to ˜90° C. is employed; heat can beremoved by external cooling and/or cooling by evaporation of the monomeror the solvent. The polymerization pressure employed may vary widely,although typically a pressure of from about 0.1 to about 1 MPa isemployed.

Where 1,3-butadiene is polymerized, the cis-1,4-polybutadiene generallyhas a M_(n), as determined by GPC using polystyrene standards, of from˜5000 to ˜200,000 Daltons, from ˜25,000 to ˜150,000 Daltons, or from˜50,000 to ˜125,000 Daltons. The polydispersity of the polymersgenerally ranges from ˜1.5 to ˜5.0, typically from ˜2.0 to ˜4.0.

Resulting polydienes advantageously can have a cis-1,4-linkage contentof at least ˜60%, at least ˜75%, at least ˜90%, and even at least ˜95%,and a 1,2-linkage content of less than ˜7%, less than ˜5%, less than˜2%, and even less than ˜1%.

Regardless of the type of polymerization process employed, at this pointthe reaction mixture commonly is referred to as a “polymer cement”because of its relatively high concentration of polymer.

Providing a terminal functionality of the type set forth above informula (IV) can be achieved by functionalizing the polymer prior toquenching, advantageously when it is in the above-described polymercement state. One method of effecting this functionalization involvesintroducing to the polymer cement one or more aromatic compounds thatinclude a group capable of reacting with terminally active polymers aswell as one or more hydroxyl groups or hydrolyzable groups (i.e., one ormore OR⁴ substituents) and allowing such compound(s) to react at aterminus of a reactive polymer chain. This type of compound hereinafteris referred to as a terminating compound.

Where the terminating compound includes more than one OR⁴ substituent,each can be on the same ring of the aryl group, or two or more can be ondifferent rings within the aryl group. Where the aryl group containsthree or more OR⁴ substituents, all of them can be on the same ring, twoof them can be on one ring with the other(s) being on other ring(s), oreach of them can be on separate rings.

A preferred group of terminating compounds include those with an arylgroup having at least two OR⁴ substituents and, among these, preferredare those where at least two of the OR⁴ substituents are on the samering of the aryl group. Among the latter, particularly preferred arethose with OR⁴ substituents at the 3 and 4 positions of the same ringwithin the aryl group, preferably a phenyl group.

Examples of compounds that can be used to provide functionality such asthat shown in formula (IV) include those with the following generalformulas:

where each R⁵ independently is a hydrogen atom, a hydroxyl group, analkoxy group, or a hydrocarbyl group, preferably an alkyl group and morepreferably a C₁-C₃ alkyl group; in certain embodiments, each R⁵ can beH. In addition to the foregoing, two or more R⁵ groups together can formanother ring such as, for example, anthrones and flavones:

By comparing formulas (VIIf) and (VIIg) to formula (IV) above, one cansee that, in the terminal functionality represented by formula (IV), R⁶and a portion of R³ can be linked so that, together with the atom(s) towhich each is attached (directly or indirectly), they form a ring thatis bound to or fused with the R³ aryl group; this can be representedpictorially by the general formula

where each of the variables is defined as before.

The foregoing are to be considered exemplary and not limiting. Forexample, each of the foregoing representative compounds include adjacenthydroxyl substituent groups (although formula (VIIf) does include onering with non-adjacent hydroxyl substituents) but, as already described,the hydroxyl substituents need not be adjacent. Not specifically shownin the foregoing formulas (VIIa)-(VIIg) but included within the scope ofuseful compounds are those having aryl groups other than phenyl groups,those having aryl groups not directly bonded to the carbonyl C atom,those with the carbonyl C atom bonded to an S atom rather than O (i.e.,thioketo analogs), those where Z′ is other than a single bond, and thelike. Where R³ is other than a phenyl group, the hydroxyl substituentgroups can be on the same or different rings; when they are on more thanone ring, it is preferred that they be at least somewhat proximate,i.e., that they be directly bonded to ring C atoms that are separated byno more than 4, preferably 3, and even more preferably 2, other ringatoms.

Further, as suggested above, the compound itself need not includehydroxyl groups and, instead, can include groups that are easilyhydrolyzable so as to provide hydroxyl groups after reaction. Protectedcompounds generally have structures similar to those set forth abovewith respect to formulas (VIIa)-(VIIg) with OR groups in place of someor all of the OH groups. By way of non-limiting example, a protectedcompound generally analogous to the compound from formula (VIIa), witheach R⁵ being H, can be represented by

where each R¹¹ independently is a hydrocarbyl group, e.g., a linear orbranched alkyl group. Variations similar to those described above withrespect to the hydroxyl-containing compounds are envisioned for theprotected compounds.

Each of the compounds represented by formulas (VIIa)-(VIIg) and (VIII)include a carbonyl group. Carbonyl groups provide convenient points forreaction with and attachment to carbanionic polymer chains. Non-limitingexamples of other potentially useful reactive groups include aldehyde,(thio)ketone, (thio)ester, di(thio)ester, amide, epoxy, halosilane, andthe like.

Reaction of these types of compound with a pre-made reactive polymer canbe performed relatively quickly (a few minutes to a few hours) atmoderate temperatures (e.g., 0° to 75° C.).

The amount of such compounds to be reacted with pre-made reactivepolymers can vary widely, depending significantly on the degree ofdesired effect, the amount of non-conventional filler(s) employed, theratio of conventional-to-non-conventional filler particles, and thelike. Based on the amount of reactive polymer chains (generallydetermined based on the equivalents of initiator or catalyst), theamount of compounds generally corresponding to formulas (VIIa)-(VIIg)and (VIII) can range from about 1:10 to about 5:4, generally from about1:5 to about 9:8, and typically from about 1:2 to about 1:1.

Lesser amounts of terminating compounds of the type just described canbe employed in certain embodiments so as to preserve some reactivepolymer terminals for reaction with other functionalizing agents, whichcan be added before, after, or with the compounds just discussed; thistype of multiple functionalization can be avoided, at least to someextent, through use of functional initiators as discussed previously.Also, at least some embodiments of polymers having functionalitiesdefined by formulas (IV) and (IVb), as well as protected analogs, canexhibit excellent interactivity with carbon black and silica, therebyavoiding the need for multiple functionalization reactions.

Where the foregoing type of terminating compound is not employed but themacromolecule includes at least one functionalizing unit derived fromeither or both of the initiator and a formula (V)-type monomer,additional functionalization can result from termination with aheteroatom-containing compound including, but not limited to, Sn, Si,and N. Specific examples of alternative or additional terminatingcompounds include 1,3-dimethyl-2-imidazolidinone (DMI),3-bis(trimethylsilyl)aminopropyl-methyldiethoxysilane (APMDEOS), as wellas those described in U.S. Pat. Nos. 3,109,871, 4,647,625, 4,677,153,5,109,907, and 6,977,281, and references cited in, and laterpublications citing, these patents. This type of functionalization isdescribed below in Examples 73-75.

At this point, the resulting polymer includes one or more types ofpolyene mer and at least one functionalizing unit which includes an arylgroup having at least one directly bonded OR⁴ substituent. Thefunctionalizing unit(s) can be derived from the initiating compound, themonomer(s), or a terminating compound. In certain aspects, more than oneof the functionalizing units can be incorporated, and these can resultfrom multiple mer, from an initiator plus one or more mer, a terminatinggroup plus one or more mer, or from all three.

The identity of the R⁴ moiety of the substituent (i.e., whether it is aH atom or a protecting group) depends on the origin of the unit of whichit is a part. Units derived from an initiator and/or monomers will haveOR groups while units derived from a terminating compound can have OR orOH groups. Ensuring that most, preferably all, R moieties are convertedto H atoms typically is desirable so as to promote maximum interactivitywith filler particles (when the polymer is used as part of a rubbercomposition). The processing steps (including quenching) described belowcan be sufficient to hydrolyze at least some of the R moieties, therebyproviding one or more hydroxyl substituents to one or more aryl groupswithin polymer. Alternatively, a separate reaction step designed topromote extensive, preferably complete, hydrolysis can be employed; fromthe exemplary technique employed in several of the examples below, theordinarily skilled artisan can envision other potentially effectivereactions. Further, the ordinarily skilled artisan understands that ORor OH groups, whether present in an R¹ group, R³ group, R⁶ group, orelsewhere, may undergo further reaction during this processing and/orcompounding with one or more types of particulate fillers (describedbelow).

Quenching can be conducted by stirring the polymer and an activehydrogen-containing compound, such as an alcohol or acid, for up toabout 120 minutes at temperatures of from about 25° to about 150° C.

Solvent can be removed from the quenched polymer cement by conventionaltechniques such as drum drying, extruder drying, vacuum drying or thelike, which may be combined with coagulation with water, alcohol orsteam, thermal desolvation, etc.; if coagulation is performed, ovendrying may be desirable.

The resulting polymer can be utilized in a tread stock compound or canbe blended with any conventionally employed tread stock rubber includingnatural rubber and/or non-functionalized synthetic rubbers such as,e.g., one or more of homo- and interpolymers that include justpolyene-derived mer units (e.g., poly(butadiene), poly(isoprene), andcopolymers incorporating butadiene, isoprene, and the like), SBR, butylrubber, neoprene, EPR, EPDM, NBR, silicone rubber, fluoroelastomers,ethylene/acrylic rubber, EVA, epichlorohydrin rubbers, chlorinatedpolyethylene rubbers, chlorosulfonated polyethylene rubbers,hydrogenated nitrile rubber, tetrafluoroethylene/propylene rubber andthe like. When a functionalized polymer(s) is blended with conventionalrubber(s), the amounts can vary from about 5 to about 99% of the totalrubber, with the conventional rubber(s) making up the balance of thetotal rubber. The minimum amount depends to a significant extent on thedegree of hysteresis reduction desired.

Elastomeric compounds typically are filled to a volume fraction, whichis the total volume of filler(s) added divided by the total volume ofthe elastomeric stock, of about 25%; accordingly, typical (combined)amounts of reinforcing fillers is about 30 to 100 phr.

Potentially useful carbon black materials include, but not limited to,furnace blacks, channel blacks and lamp blacks. More specifically,examples of the carbon blacks include super abrasion furnace blacks,high abrasion furnace blacks, fast extrusion furnace blacks, finefurnace blacks, intermediate super abrasion furnace blacks,semi-reinforcing furnace blacks, medium processing channel blacks, hardprocessing channel blacks, conducting channel blacks, and acetyleneblacks; mixtures of two or more of these can be used. Carbon blackshaving a surface area (EMSA) of at least 20 m²/g, preferably at leastabout 35 m²/g, are preferred; surface area values can be determined byASTM D-1765. The carbon blacks may be in pelletized form or anunpelletized flocculent mass, although unpelletized carbon black can bepreferred for use in certain mixers.

The amount of carbon black utilized historically has been up to ˜50parts by weight (pbw) per 100 parts of polymer (phr), with ˜5 to ˜40 phrbeing typical. For certain oil-extended formulations, the amount ofcarbon black has been even higher, e.g., on the order of ˜80 phr.

Amorphous silica (SiO₂) also commonly is used as a filler. Silicastypically are produced by a chemical reaction in water, from which theyare precipitated as ultrafine, spherical particles which stronglyassociate into aggregates and, in turn, combine less strongly intoagglomerates. Surface area gives a reliable measure of the reinforcingcharacter of different silicas, with BET (see; Brunauer et al., J. Am.Chem. Soc., vol. 60, p. 309 et seq.) surface areas of less than 450m²/g, commonly between ˜32 to ˜400 m²/g, and typically ˜100 to ˜250m²/g, generally being considered useful. Commercial suppliers of silicainclude PPG Industries, Inc. (Pittsburgh, Pa.), Grace Davison(Baltimore, Md.), Degussa Corp. (Parsippany, N.J.), Rhodia SilicaSystems (Cranbury, N.J.), and J.M. Huber Corp. (Edison, N.J.).

When silica is employed as a reinforcing filler, addition of a couplingagent such as a silane is customary so as to ensure good mixing in, andinteraction with, the elastomer(s). Generally, the amount of silane thatis added ranges between about 4 and 20%, based on the weight of silicafiller present in the compound. Coupling agents can have a generalformula of A-T-G, in which A represents a functional group capable ofbonding physically and/or chemically with a group on the surface of thesilica filler (e.g., surface silanol groups); T represents a hydrocarbongroup linkage; and G represents a functional group capable of bondingwith the elastomer (e.g., via a sulfur-containing linkage). Suchcoupling agents include organosilanes, in particular polysulfurizedalkoxysilanes (see, e.g., U.S. Pat. Nos. 3,873,489, 3,978,103,3,997,581, 4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,684,171,5,684,172, 5,696,197, etc.) or polyorganosiloxanes bearing the G and Afunctionalities mentioned above. Addition of a processing aid can beused to reduce the amount of silane employed; see, e.g., U.S. Pat. No.6,525,118 for a description of fatty acid esters of sugars used asprocessing aids. Additional fillers useful as processing aids includemineral fillers, such as clay (hydrous aluminum silicate), talc (hydrousmagnesium silicate), and mica as well as non-mineral fillers such asurea and sodium sulfate. Preferred micas contain principally alumina,silica and potash, although other variants also can be useful. Theadditional fillers can be utilized in an amount of up to about 40 phr,typically up to about 20 phr.

Silica commonly is employed in amounts of up to ˜100 phr, typically from˜5 to ˜80 phr. The useful upper range is limited by the high viscositythat such fillers can impart. When carbon black also is used, the amountof silica can be decreased to as low as ˜1 phr; as the amount of silicadecreases, lesser amounts of the processing aids, plus silane if any,can be employed.

One or more non-conventional fillers having relatively high interfacialfree energies, i.e., surface free energy in water values (γ_(pl))preferably are used in conjunction with or in place of carbon blackand/or silica. The term “relatively high” can be defined orcharacterized in a variety of ways such as, e.g., greater than that ofthe water-air interface, preferably several multiples (e.g., at least2×, at least 3× or even at least 4×) of this value; at least severalmultiples (e.g., at least 2×, at least 3×, at least 4×, at least 5×, atleast 6×, at least 7×, at least 8×, at least 9× or even at least 10×) ofthe γ_(pl) value for amorphous silica; in absolute terms such as, e.g.,at least ˜300, at least ˜400, at least ˜500, at least ˜600, at least˜700, at least ˜750, at least ˜1000, at least ˜1500, and at least ˜2000mJ/m²; in ranges such as, e.g., from ˜300 to ˜5000 mJ/m², from ˜350 to˜4000 mJ/m², from ˜400 to ˜5000 mJ/m², from ˜450 to ˜4000 mJ/m², from˜500 to ˜5000 mJ/m², and various sub-ranges within the foregoing and/orother combinations of high and low values; and the like.

Non-limiting examples of naturally occurring materials with relativelyhigh interfacial free energies include F-apatite, goethite, hematite,zincite, tenorite, gibbsite, quartz, kaolinite, all forms of pyrite, andthe like. Certain synthetic complex oxides also can exhibit this type ofhigh interfacial free energy.

The foregoing types of materials typically are more dense than eithercarbon black or amorphous silica; thus, replacing a particular mass ofcarbon black or silica with an equal mass of a non-conventional fillertypically will result in a much smaller volume of overall filler beingpresent in a given compound. Accordingly, replacement typically is madeon an equal volume, as opposed to equal weight, basis.

Generally, ˜5 to ˜60% of the conventional particulate filler material(s)can be replaced with an approximately equivalent (˜0.8× to ˜1.2×) volumeof non-conventional filler particles. In certain embodiments, replacing˜10 to ˜58% of the conventional particulate filler material(s) with anapproximately equivalent (˜0.85× to ˜1.15×) volume of other fillerparticles is sufficient; in other embodiments, replacing ˜15 to ˜55% ofthe conventional particulate filler material(s) with an approximatelyequivalent (˜0.9× to ˜1.1×) volume of other filler particles isadequate; in still other embodiments, replacing ˜18 to ˜53% of theconventional particulate filler material(s) with an approximatelyequivalent (˜0.95× to ˜1.05×) volume of other filler particles can bepreferable.

The weight inequality issue might be able to be overcome or amelioratedby employing non-standard particles. For example, one can envisionessentially hollow particles of one or more types of non-conventionalfillers as well as relatively light particles coated so as to have asurface that includes one or more of types of non-conventional fillercompounds.

The non-conventional filler particles generally can be of approximatelythe same size as the conventional fillers employed in compounds. Inother words, neither extremely large particles such as those employed inthe aforementioned U.S. Pat. No. 5,066,702 nor extremely small particlessuch as those employed in the aforementioned U.S. Pat. No. 6,972,307 arerequired. In general, relatively small particles are preferred both forreinforcement purposes and to ensure a large number of particles areavailable at the tread surface.

Other conventional rubber additives also can be added. These include,for example, process oils, plasticizers, anti-degradants such asantioxidants and antiozonants, curing agents and the like.

All ingredients can be mixed with standard equipment such as, e.g.,Banbury or Brabender mixers. Typically, mixing occurs in two or morestages. During the first stage (also known as the masterbatch stage),mixing typically is begun at temperatures of ˜120° to ˜130° C. andincreases until a so-called drop temperature, typically ˜165° C., isreached.

Where a formulation includes fillers other than carbon black, a separatere-mill stage often is employed for separate addition of the silanecomponent(s). This stage often is performed at temperatures similar to,although often slightly lower than, those employed in the masterbatchstage, i.e., ramping from ˜90° C. to a drop temperature of ˜150° C.

Reinforced rubber compounds conventionally are cured with about 0.2 toabout 5 phr of one or more known vulcanizing agents such as, forexample, sulfur or peroxide-based curing systems. For a generaldisclosure of suitable vulcanizing agents, the interested reader isdirected to an overview such as that provided in Kirk-Othmer,Encyclopedia of Chem. Tech., 3d ed., (Wiley Interscience, New York,1982), vol. 20, pp. 365-468. Vulcanizing agents, accelerators, etc., areadded at a final mixing stage. To avoid undesirable scorching and/orpremature onset of vulcanization, this mixing step often is done atlower temperatures, e.g., starting at ˜60° to ˜65° C. and not goinghigher than ˜105° to ˜110° C.

Subsequently, the compounded mixture is processed (e.g., milled) intosheets prior to being formed into any of a variety of components andthen vulcanized, which typically occurs at ˜5° to ˜15° C. higher thanthe highest temperatures employed during the mixing stages, mostcommonly about 170° C.

The following non-limiting, illustrative examples provide detailedconditions and materials that can be useful in the practice of theinvention just described.

EXAMPLES

In all examples, dried glass vessels previously sealed with extractedseptum liners and perforated crown caps under a positive N₂ purge wereused for all preparations.

All nuclear magnetic resonance (NMR) testing was performed on a Varian™300 MHz spectrometer (Varian, Inc.; Palo Alto, Calif.).

Data corresponding to “Bound rubber” were determined using the proceduredescribed by J. J. Brennan et al., Rubber Chem. and Tech., 40, 817(1967).

Cold flow testing was performed using a Scott™ tester. Samples wereprepared by melt pressing 2.5 g of polymer at 100° C. for 20 minutes ina mold using a preheated press. The resulting cylindrical samples, whichhad a uniform thickness of ˜12 mm, were allowed to cool to roomtemperature before being removed from the mold. Samples were placedindividually under the weight of a 5 kg calibrated weight. Tests wereconducted for ˜30 min. for SBR samples and ˜8 min. for polybutadienesamples (measured from time that the weight was released), with samplethicknesses being recorded as a function of time. Sample thickness atthe conclusion of the appropriate time (˜30 min. or ˜8 min.) generallyis considered to be an acceptable indicator of cold flow resistance.

Mooney viscosity (ML₁₊₄) values were determined with an AlphaTechnologies™ Mooney viscometer (large rotor) using a one-minute warm-uptime and a four-minute running time; tensile mechanical properties weredetermined using the standard procedure described in ASTM-D412; Payneeffect (ΔG′, i.e., the difference between G′ at 0.25% strain and at 14%strain) and hysteresis (tan δ) data were obtained from dynamicexperiments conducted at 60° C. and 10 Hz (strain sweep) and 2% strainand 10 Hz (temperature sweep). With respect to tensile properties, M_(Y)is modulus at Y % elongation, T_(b) is tensile strength at break, andE_(b) is percent elongation at break.

A. Examples 1-33 (Terminators)

In these examples, styrene (33% in hexane), hexane, n-butyllithium (1.60M in hexane), 2,2-bis(2′-tetrahydrofuryl)propane (1.6 M solution inhexane, stored over CaH₂), and 2,6-di-tert-butyl-4-methylphenol (BHT)solution in hexane were used.

Commercially available reagents and starting materials included thefollowing, all of which were acquired from Sigma-Aldrich Co. (St. Louis,Mo.) and used without further purification unless otherwise noted in aspecific example: 3,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzophenone,imidazole, t-butyl(chloro)dimethylsilane, diethyl ether, NH₄Cl, MgSO₄(anhydrous), THF, ethyl acetate, methylaluminoxane (MAO),diisobutylaluminum hydride, HMI, diethylaluminum chloride,4,4′-bis(diethylamino)benzophenone (DEAB), and tetrabutyl-ammoniumfluoride (TBAF).

Testing data in most of the Examples was performed on filledcompositions made according to the formulations shown below in

-   -   Table 1a (titanium oxide, rutile),    -   Table 1b (carbon black and aluminum hydroxide),    -   Table 1c (carbon black and titanium oxide), and    -   Table 1d (carbon black).        The titania employed in these formulations was Tronox™ CR-834        alumina-stabilized TiO₂ with a particle size of ˜0.17 μm and a        specific gravity of ˜4.2 (Tronox Inc.; Oklahoma City, Okla.),        and the aluminum hydroxide employed was Hydral™ PGA-HD Al(OH)₃        particles with a median particle diameter of ˜1 μm and a density        of 2.42 g/cm³ (Almatis, Inc.; Leetsdale, Pa.). In these (and        similar subsequent tables),        N-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD) acts        as an antioxidant, and 2,2′-dithiobis(benzothiazole) (MBTS),        N-tert-butylbenzothiazole-2-sulfenamide (TBBS) and        N,N′-diphenylguanidine (DPG) act as accelerators. Black oil is        an extender oil that contains a relatively low amount of        polycyclic aromatic (PCA) compounds.

TABLE 1a Compound formulation, titania Amount (phr) Masterbatchsynthetic polymer 100 TiO₂ 116.7 6PPD 1 stearic acid 2 Final sulfur 1.3ZnO 3 TBBS 1 MBTS 1 DPG 0.5 TOTAL 226.5

TABLE 1b Compound formulation, carbon black and aluminum hydroxideAmount (phr) Masterbatch synthetic polymer 100 carbon black (N339 type)25 Al(OH)₃ 33.6 6PPD 1 stearic acid 2 Final sulfur 1.5 ZnO 3 MBTS 1 DPG0.5 TOTAL 167.6

TABLE 1c Compound formulation, carbon black and titania Amount (phr)Masterbatch synthetic polymer 100 carbon black (N339 type) 25 TiO₂ 58.36PPD 1 stearic acid 2 Final sulfur 1.3 ZnO 3 TBBS 1 MBTS 1 DPG 0.5 TOTAL193.1

TABLE 1d Compound formulation, carbon black Amount (phr) Masterbatchsynthetic polymer 80 polyisoprene 20 carbon black (N343 type) 50 wax 26PPD 1 stearic acid 2 black oil 10 Final sulfur 1.5 ZnO 2.5 MBTS 0.5TBBS 0.5 DPG 0.3 TOTAL 170.3

Example 1: Synthesis of 3,4-bis(tert-butyldimethylsilyloxy)benzophenone

To a dry flask under nitrogen was charged ˜6.0 g3,4-dihydroxybenzophenone, ˜6.3 g triethylamine, ˜0.14 g4-(dimethylamino)pyridine, and 30 mL DMF. A solution of ˜9.3 gtert-butyl(chloro)dimethylsilane in 30 mL DMF then was added in dropwisefashion.

The reaction mixture was stirred for ˜4 hours at room temperature beforebeing poured into ˜100 mL hexane and ˜30 mL saturated NH₄Cl solution.The organic phase was washed three times with 50 mL portions of waterand dried with anhydrous MgSO₄.

After solvent was removed, the residue was separated by a flashsilica-gel column with hexane/ethyl acetate (85:15, v/v) as eluent.Approximately 11.5 g (93% yield) white solid was obtained. Proton and¹³C NMR spectroscopic analysis confirmed the product as3,4-bis(tert-butyldimethylsilyloxy)benzophenone (BTBDMSBP).

Example 2: Synthesis of 3,4-bis(tert-butyldimethylsilyloxy)benzaldehyde

To a dry flask under nitrogen was charged ˜10.0 g3,4-dihydroxybenzaldehyde, ˜16.1 g triethylamine, ˜0.35 g4-(dimethylamino)pyridine, and 60 mL DMF. A solution of ˜24.0 gtert-butyl(chloro)dimethylsilane in 60 mL DMF then was added in dropwisefashion.

The reaction mixture was stirred for ˜4 hours at room temperature beforebeing poured into ˜200 mL hexane and ˜100 mL saturated NH₄Cl solution.The organic phase was washed three times with 100 mL portions of waterand dried with anhydrous MgSO₄.

After solvent was removed, the residue was separated by a flashsilica-gel column with hexane/ethyl acetate (95:5, v/v) as eluent.Approximately 25.5 g (96% yield) white solid was obtained. Proton and¹³C NMR spectroscopic analysis confirmed the product as3,4-bis(tert-butyldimethylsilyloxy)benzaldehyde (BTBDMSBA).

Examples 3-5: Styrene/Butadiene Copolymers

To a N₂-purged reactor equipped with a stirrer was added 1.39 kg hexane,0.37 kg styrene solution, and 2.27 kg butadiene solution (21.6% by wt.in hexane). The reactor was charged with 3.19 mL n-butyllithiumsolution, followed by 1.13 mL of 2,2-bis(2′-tetrahydro-furyl)propanesolution. The reactor jacket was heated to 50° C., and thepolymerization was allowed to continue for ˜75 minutes. The polymercement was cooled to room temperature before being quenched inisopropanol containing 2,6-di-tert-butyl-4-methylphenol and then drumdried. This is designated Example 3 below.

The foregoing polymerization was essentially repeated; however, prior tocoagulation, 6.0 mL of a 0.83 M solution of BTBDMSBP (from Example 1) inhexane was added to the reactor, and the polymer cement was agitated foranother ˜30 minutes at 50° C. before being allowed to cool to roomtemperature. The polymer cement was transferred to a N₂-purged bottle,to which ˜130 mL TBAF solution (0.23 M in THF) was added. The bottle wasrotated for ˜4 hours in a 25° C. water bath followed by another ˜30minutes in a 50° C. water bath. The bottle contents then were coagulatedand drum dried as above. This is designated Example 4 below.

The polymerization again was essentially repeated, with the exceptionthat ˜2.24 kg of 21.9% by wt. butadiene solution was used. Prior tocoagulation, 4.9 mL of a 1.0 M solution of BTBDMSBA (from Example 2) inhexane was added to the reactor, and the polymer cement was processedsimilarly to the one from Example 4. This is designated as Example 5below.

The properties of these styrene/butadiene copolymers are summarized inthe following table. Molecular weights were determined by GPC using SBRstandards, and 1,2-linkage contents were determined from ¹H NMRspectroscopy.

TABLE 2 Properties of polymers from Examples 3-5 3 4 5 M_(n) (kg/mol)109.5 110.0 120.3 M_(w)/M_(n) 1.05 1.08 1.12 T_(g) (° C.) −38.4 −38.4−39.2 styrene content (%) 21.0 20.9 21.1 1,2-linkage content (%) 49.149.0 48.6

Examples 6-11: Filled Compositions

The polymers from Examples 3-5 were used with the formulation shownabove in Table 1a to provide compositions from which vulcanizatesdesignated as Examples 6-8 below were prepared.

The same polymers were used with the formulation shown above in Table 1bto provide compositions from which vulcanizates designated as Examples9-11 below were prepared.

Mixing of each compound (i.e., filled composition) was performed with a65 g Brabender™ internal mixer. After vulcanization under high pressureat high temperature, physical properties of the compounds weredetermined, and the results are summarized below in Table 3.

TABLE 3 Testing data from Examples 6-11 6 7 8 9 10 11 Compoundformulation Table 1a Table 1b Polymer used (example no.) 3 4 5 3 4 5Shore A hardness @ 23° C. 40.7 48.5 48.8 57.3 58.1 57.4 Rebound @ 50° C.49.8 63.8 64.8 46.0 55.0 55.4 Tensile testing, 23° C. Modulus, 50%strain (MPa) 0.589 1.068 1.108 1.670 1.861 1.804 Modulus, 100% strain(MPa) 0.779 1.915 2.034 2.677 3.682 3.649 Modulus, 200% strain (MPa)1.233 4.182 4.783 5.068 7.723 8.021 Modulus, 300% strain (MPa) 1.9195.988 7.115 8.137 12.847 13.115 T_(b) (MPa) 3.4 6.9 8.4 10.3 16.2 14.9E_(b) (%) 415.2 346.3 359.8 354.0 355.7 327.8 Temperature sweep, 10 HzTemp. at tan δ peak (° C.) −21.12 −20.36 −20.79 −20.04 −19.41 −19.83 G′@ −20° C. and 0.20% strain (MPa) 50.8 23.3 20.1 104.0 59.6 49.2 Strainsweep, 60° C. and 10 Hz G′ @ 6.96% strain (MPa) 1.34 1.44 1.48 2.12 2.112.08 tan δ @ 6.96% strain 0.125 0.0585 0.0557 0.172 0.0835 0.0799

Relative to Examples 6 and 9 (non-functionalized controls),respectively, Examples 7-8 and 10-11 displayed significantly higher roomtemperature Shore A hardness values, significantly higher rebound valuesat 50° C. (generally corresponding to reductions in hysteresis),enhanced room temperature tensile strengths, lower modulus values at−20° C. (generally corresponding to better ice traction), higher elasticmodulus at 60° C. and high strain (generally corresponding to betterhandling performance) and significantly lower loss tangent at 60° C.(generally corresponding to reductions in hysteresis).

Examples 12-14: Functionally Initiated Styrene/Butadiene Copolymers

To a N₂-purged reactor equipped with a stirrer was added 1.39 kg hexane,0.37 kg styrene solution, and 2.27 kg butadiene solution (21.6% by wt.in hexane). The reactor was charged with 1.62 mL of 3.0 M HMI in tolueneand 3.19 mL n-butyllithium solution, followed by 1.13 mL2,2-bis(2′-tetrahydrofuryl)propane solution. The reactor jacket washeated to 50° C., and the polymerization was allowed to continue for ˜60minutes. The polymer cement was cooled to room temperature before beingquenched and drum dried as described previously. This is designatedExample 12 below.

The foregoing polymerization was essentially repeated; however, thepolymerization was permitted to continue for ˜75 minutes at 50° C. and,prior to coagulation, 6.0 mL of a 0.83 M solution of BTBDMSBP (fromExample 1) in hexane was added to the reactor, and the polymer cementwas agitated for another ˜30 minutes at 50° C. before being allowed tocool to room temperature. The polymer cement was transferred to aN₂-purged bottle, to which ˜130 mL TBAF solution (0.23 M in THF) wasadded. The bottle was rotated for ˜4 hours in a 25° C. water bathfollowed by another ˜30 minutes in a 50° C. water bath. The bottlecontents then were coagulated and drum dried as above. This isdesignated Example 13 below.

The polymerization and processing described in connection with Example13 again was essentially repeated, with the exception that ˜2.24 kg of21.9% by wt. butadiene solution was used and, prior to coagulation, 4.9mL of a 1.0 M solution of BTBDMSBA (from Example 2) in hexane was addedto the reactor. This is designated Example 14 below.

The properties of these copolymers are summarized in the followingtable.

TABLE 4 Properties of polymers from Examples 12-14 12 13 14 M_(n)(kg/mol) 106.4 112.7 116.7 M_(w)/M_(n) 1.06 1.14 1.14 T_(g) (° C.) −38.1−38.7 −40.6 styrene content (%) 21.8 21.5 20.5 1,2-linkage content (%)48.0 48.4 47.7

Examples 15-20: Filled Compositions

The polymers from Examples 12-14 were used with the formulation shown inTable 1c above to provide compositions from which vulcanizatesdesignated as Examples 15-17 respectively below were prepared.

The same polymers were used with the formulation shown above in Table 1bto provide other compositions from which vulcanizates designated asExamples 18-20 below were prepared.

Mixing, vulcanization, and testing on these filled compositions wereconducted similar to those described above in connection with Examples6-11. Physical properties are summarized below in Table 5.

TABLE 5 Testing data from Examples 15-20 15 16 17 18 19 20 Compoundformulation Table 1c Table 1b Polymer used (example no.) 12 13 14 12 1314 Shore A hardness @ 23° C. 53.1 57.1 58.0 55.8 59.3 59.1 Rebound @ 50°C. 54.6 60.0 61.0 52.0 56.2 56.4 Tensile testing, 23° C. Modulus, 50%strain (MPa) 1.305 1.691 1.695 1.595 1.943 1.900 Modulus, 100% strain(MPa) 2.217 3.390 3.514 2.694 3.793 3.784 Modulus, 200% strain (MPa)5.343 8.367 9.156 5.350 7.899 8.336 Modulus, 300% strain (MPa) 9.978 — —9.102 13.06 — T_(b) (MPa) 12.5 13.7 13.6 10.6 15.6 12.3 E_(b) (%) 345.1293.1 270.6 331.4 343.7 274.6 Temperature sweep, 10 Hz Temp. at tan δpeak (° C.) −22.87 −22.35 −23.59 −19.96 −19.87 −20.05 G′ @ −20° C. and0.20% strain (MPa) 40.7 31.4 22.1 63.1 55.6 34.6 Strain sweep, 60° C.and 10 Hz G′ @ 6.96% strain (MPa) 1.91 2.18 2.08 1.99 2.28 2.18 tan δ @6.96% strain 0.110 0.0741 0.0702 0.115 0.0735 0.0730

The data from Table 5 display trends similar to those seen above inconnection with Table 3.

Example 21: Synthesis of 3,4-bis(trimethylsilyloxy)benzaldehyde

To a dry flask was charged ˜4.83 g 3,4-dihydroxybenzaldehyde, ˜4.80 gimidazole, and 50 mL THF under nitrogen. The solution was cooled to −78°C. before ˜43.8 mL of a 1.6 M solution of n-butyllithium was added indropwise fashion.

The reaction mixture was warmed to room temperature before ˜7.61 gchlorotrimethylsilane was added in dropwise fashion, and then thereaction mixture was stirred for ˜2 hours at room temperature.

After LiCl precipitated to the bottom of the vessel, the ˜0.33 M3,4-bis(trimethyl-silyloxy)benzaldehyde (BTMSBA) was used immediately asa terminating compound in Examples 26-27 below.

Examples 22-27: Cis-1,4-polybutadienes

Catalysts were prepared by adding to dried, capped, N₂-flushed bottlesthe following ingredients:

TABLE 6 Catalyst ingredients A B C D butadiene in hexane % by wt. 21.422.2 21.4 22.2 amount (g) 1.6 3.0 3.6 3.6 MAO (1.51M), mL 5.96 4.68 5.675.67 neodymium versatate (0.050M), mL 5.15 4.04 4.90 4.90diisobutylaluminum hydride (1.0M), mL 5.40 4.24 5.14 5.14diethylaluminum chloride (1.0M), mL 1.03 0.81 0.98 0.98The mixtures were aged for 15 minutes at room temperature prior to usein the following polymerizations.

To a N₂-purged reactor equipped with a stirrer was added 1.22 kg hexaneand 2.86 kg butadiene solution (21.4% by wt. in hexane). The reactor wascharged with the catalyst mixture A, and the jacket temperature was setto 60° C. The polymerization was allowed to continue for ˜60 minutes.The polymer cement was cooled to room temperature before being quenchedand drum dried as described previously. This is designated Example 22below.

The foregoing polymerization was essentially repeated three more times.In the first, 1.32 kg hexane, 2.76 kg butadiene solution (22.2% by wt.in hexane), as well as catalyst mixture B were used. This is designatedExample 23 below.

In the second, catalyst mixture C was used and, prior to coagulation,0.5 M DEAB in toluene (1.25 mL per 100 g polymer cement) was added andallowed to react for ˜30 minutes in a 65° C. water bath. This isdesignated Example 24 below.

In the third, 1.32 kg hexane, 2.76 kg butadiene solution (22.2% by wt.in hexane), as well as catalyst mixture D were used. Three separateportions of the polymer cement were transferred to bottles and processedas follows before being quenched and drum dried as described previously.

-   -   Example 25: 1.0 M BTBDMSBA (from Example 2) in hexane (0.3 mL        per 100 g polymer cement) was added and permitted to react with        the cement for ˜30 min. in a 65° C. water bath before TBAF        solution (1.0 M in THF, 0.7 mL per 100 g polymer cement) was        added, and the bottle was rotated in a 25° C. water bath for ˜4        hours.    -   Example 26: 0.33 M BTMSBA (from Example 21) in hexane (0.91 mL        per 100 g polymer cement) was added and permitted to react with        the cement for ˜30 min. in a 65° C. water bath.    -   Example 27: 0.33 M BTMSBA (from Example 21) in hexane (0.91 mL        per 100 g polymer cement) was added and permitted to react with        the cement for ˜30 min. in a 65° C. water bath before 1.0 M HCl        in isopropanol (1.0 mL per 100 g polymer cement) was added, and        the bottle was rotated in a 50° C. water bath for ˜30 min.

The properties of these polybutadienes are summarized in the followingtable. As before, molecular weights were determined by GPC, but themicrostructure of the polymers was determined by IR spectroscopicanalysis. Cold flow resistance values were determined as describedabove.

TABLE 7 Properties of polymers from Examples 22-27 22 23 24 25 26 27M_(n) (kg/mol) 117.8 132.9 117.4 121.3 108.6 120.5 M_(w)/M_(n) 2.14 2.182.16 2.22 2.49 2.25 ML₁₊₄ @ 100° C. 28.2 45.7 27.9 41.6 50.6 33.7 coldflow (mm) 1.94 2.34 1.93 2.62 2.98 2.25 cis 1,4-linkage content (%) 94.896.7 94.9 95.2 95.6 95.3 trans 1,4-linkage content (%) 4.6 2.8 4.6 4.33.9 4.2 1,2-linkage content (%) 0.6 0.5 0.6 0.5 0.5 0.5

Examples 28-33: Filled Compositions

The polymers from Examples 22-27 were used with the formulation shownabove in Table 1d to provide compositions from which were preparedvulcanizates designated, respectively, as Examples 28-33 below.

Mixing, vulcanization, and testing on these filled compositions wereconducted similar to those described above in connection with Examples6-11, with physical properties summarized in the following table.

TABLE 8 Testing data from Examples 28-33 28 29 30 31 32 33 Polymer used(example no.) 22 23 24 25 26 27 ML₁₊₄ @ 130° C. 53.5 71.2 54.9 70.7 65.060.5 Tensile testing, 23° C. Modulus, 300% strain (MPa) 10.48 10.6110.24 11.27 10.72 10.74 T_(b) (MPa) 17.87 18.76 14.30 14.01 13.98 14.64E_(b) (%) 447 456 383 354 365 377 tan δ @ 50° C., 3% strain, 15 Hz0.1315 0.1137 0.1120 0.1013 0.1029 0.1034 Dynastat tan δ, 50° C. and 10Hz 0.1123 0.0993 0.1008 0.0896 0.0885 0.0911

The data of Table 8 show, inter alia, that vulcanizates made withcis-1,4-polybutadienes functionalized with aryl groups that includehydroxyl substituents directly bonded to adjacent ring carbon atoms(Examples 31-33) exhibit fairly significant reductions in tan δ at 50°C. (corresponding to reductions in hysteresis) relative to vulcanizatesmade from non-functionalized control polymers (Examples 28-29) or evenfrom a comparative functionalized polymer (Example 30).

B. Examples 34-50 (Initiators)

Butadiene solutions (all in hexane), styrene (33% in hexane), hexane,n-butyllithium (n-BuLi, 1.60 M in hexane),2,2-bis(2′-tetrahydrofuryl)propane (1.6 M solution in hexane, storedover CaH₂), and butylated hydroxytoluene (BHT) solution in hexane wereused in these examples.

Commercially available reagents and starting materials included thefollowing, all of which were used without further purification unlessotherwise noted in a specific example:

-   -   from Sigma-Aldrich Co.—3,4-dihydroxybenzaldehyde (97%),        1,3-propanedithiol (99%), p-toluenesulfonic acid monohydrate        (98.5%), ethyl acetate (99.5%), and 4-di(methylamino)pyridine        (DMAP, 99%), and    -   from ACROS Organics—tert-butyldimethylsilyl chloride (98%) and        TBAF (1 M in THF, containing ˜5% water).

Testing was performed on filled compositions made according to theformulations shown in Tables 9a (a formulation employing only silica asa particulate filler) and 9b (a formulation employing only carbon blackas a particulate filler).

TABLE 9a Composition for vulcanizates, silica filler Amount (phr)Masterbatch synthesized polymer 80 poly(isoprene) (natural rubber) 20silica 52.5 wax 2 N-phenyl-N′-(1,3-dimethylbutyl)-p- 0.95phenylenediamine stearic acid 2 black oil 10 Re-mill silica 2.5 silane 5Final sulfur 1.5 ZnO 2.5 2,2′-dithiobisbenzothiazole 2.0N-t-butylbenzothiazole-2-sulfenamide 0.7 N,N′-diphenylguanidine 1.4TOTAL 183.05

TABLE 9b Composition for vulcanizates, carbon black filler Amount (phr)Masterbatch synthesized polymer 100 carbon black (N343 type) 50 wax 2N-phenyl-N′-(1,3-dimethylbutyl)-p- 0.95 phenylenediamine stearic acid 2black oil 10 Final sulfur 1.5 ZnO 2.5 2,2′-dithiobisbenzothiazole 0.5N-t-butylbenzothiazole-2-sulfenamide 0.5 N,N′-diphenylguanidine 0.3TOTAL 170.25

Example 34: 3,4-di(tert-butyldimethylsiloxy)phenyl-1,3-dithiane

To a dried 500 mL flask including a magnetic stirring bar and a refluxcondenser was added 8.2 g 3,4-dihydroxybenzaldehyde, 1.6 gp-toluenesulfonic acid monohydrate, and 100 mL THF, followed by 6 mL1,3-propanedithiol in 30 mL THF. This mixture was refluxed undernitrogen for ˜12 hours. After cooling to room temperature, the mixturewas filtered, with the filtrate being washed twice with saturated NaHCO₃(100 mL) and once with saturated NaCl solution (100 mL) before beingdried over anhydrous MgSO₄. Solvent was evaporated, and the residue waspurified using silica gel column chromatography using 50% ethyl acetatein hexane as eluting solvent. An oily product (13.3 g, 99% yield) wasobtained, and ¹H and ¹³C NMR in CDCl₃ confirmed the structure as

To a dried 500 mL flask including a magnetic stirring bar was added 13.3g of this dithiane, 0.5 g DMAP, 100 mL THF, and 30 mL triethylamine,followed by syringe addition of a solution of 18.7 gtert-butyldimethylsilyl chloride in 50 mL THF. This mixture was allowedto stir (under nitrogen) at room temperature for about an hour. Solidwas filtered out of the mixture, and solvent was evaporated before thefiltrate was purified using silica gel column chromatography using 5%ethyl acetate in hexane as eluting solvent. A white solid (24.9 g, 92%yield) was obtained, and ¹H and ¹³C NMR in CDCl₃ confirmed this productto be 3,4-di(tert-butyldimethylsiloxy)phenyl-1,3-dithiane.

The 3,5-, 2,5-, 2,3-, etc., analogs of3,4-di(tert-butyldimethylsiloxy)phenyl-1,3-dithiane can be preparedsimilarly, using the corresponding dihydroxybenzaldehydes. Also,4-(tert-butyldimethylsiloxy)phenyl-1,3-dithiane can be prepared by using4-hydroxybenzaldehyde as a starting material. All of the benzaldehydescan be obtained from a commercial supplier such as, for example,Sigma-Aldrich.

Example 35: BTBDMSBA (Alternative to Synthesis from Example 2)

To a dried 500 mL flask including a magnetic stirring bar was added ˜8.2g 3,4-dihydroxybenzaldehyde, ˜0.5 g DMAP, 100 mL THF, and 30 mLtriethylamine, followed by syringe addition of a solution of ˜19.0 gtert-butyldimethylsilyl chloride in 50 mL THF. This mixture was allowedto stir (under nitrogen) at room temperature for about an hour. Solidwas filtered out of the mixture, and solvent was evaporated before thefiltrate was purified using silica gel column chromatography using 10%ethyl acetate in hexane as eluting solvent. A waxy, oily semi-solid(21.3 g, 97% yield) was obtained. ¹H and ¹³C NMR confirmed the productto be BTBDMSBA.

Example 36: SBR (Control)

To a N₂-purged reactor equipped with a stirrer was added 1.47 kg hexane,0.41 kg styrene solution, and 2.60 kg butadiene solution (20.9% inhexane). The reactor was charged with ˜3.2 mL n-BuLi solution followedby 1.1 mL 2,2-bis(2′-tetrahydrofuryl)propane solution. The reactorjacket was heated to 50° C. and, after ˜30 minutes, the batchtemperature peaked at ˜64° C. After an additional ˜30 minutes, thepolymer cement was dropped into isopropanol containing BHT and drumdried.

This polymer is designated sample 36 in Table 10 below.

Examples 37-40: 3,4-di(tert-butyldimethylsiloxy)phenyl-1,3-dithiane asInitiator Precursor

To a N₂-purged reactor similar to that employed in Example 36 was added1.37 kg hexane, 0.41 kg styrene solution, and 2.71 kg butadiene solution(20.1% in hexane). The reactor was charged with 5.9 mL of a 1.0 Msolution of the dithiane from Example 34 in hexane followed by 3.9 mLn-BuLi solution. After ˜5 minutes, 1.1 mL2,2-bis(2′-tetrahydro-furyl)propane solution was added. The reactorjacket was heated to 50° C. and, after ˜35 minutes, the batchtemperature peaked at ˜67° C.

After an additional ˜30 minutes, portions of the polymer cement weretransferred to glass bottles and terminated with

-   -   samples 37 and 38—isopropanol,    -   sample 39—BTBDMSBA (from Example 35), 1.0 M in hexane (using a        1:1 ratio of benzaldehyde to Li atoms), and    -   sample 40—SnCl₄, 0.25 M in hexane (using a 1:1 ratio of Sn to        Li).        Each sample was agitated for an additional ˜30 min. in a 50° C.        water bath. The protecting groups from samples 5-7 were        hydrolyzed by reaction at room temperature (˜2 hours) with TBAF        solution (˜20% molar excess relative to calculated amount of        protecting groups).

Each polymer cement was coagulated and dried as in Example 36.

Properties of the polymers from Examples 36-40 are summarized below inTable 10, where M_(p) represents peak molecular weight.

TABLE 10 Polymer properties 36 37 38 39 40 M_(n) (kg/mol) 134 98 99 102137 M_(p) (kg/mol) 144 103 103 103 109 M_(w)/M_(n) 1.05 1.11 1.14 1.182.18 T_(g) (° C.) −37.7 −41.0 −41.1 −40.8 −41.4 % coupling 0 5.0 5.014.9 broad

Sample 39 showed excellent cold flow results when subjected to thetesting procedure described above.

Examples 41-49: Preparation and Testing of Vulcanizates

Using the formulations from Table 9a and 9b above, vulcanizableelastomeric compounds containing reinforcing fillers were prepared fromsamples 36-40. Those prepared from the Table 9a formulation aredenominated Examples 41-45 respectively, while those prepared from theTable 9b formulation are denominated Examples 46-50 respectively.Compounds were cured for ˜15 minutes at 171° C.

Strain sweep test results are tabulated in Tables 11a and 11b, whiletemperature sweep test results are tabulated in Tables 12a and 12b.

TABLE 11a Results of strain sweep testing @ 60° C., Examples 41-45 41 4243 44 45 Strain (sample 36) (sample 37) (sample 38) (sample 39) (sample40) (%) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) tanδ G′ (MPa) 0.249 0.0706 8.25 0.0648 7.79 0.0621 3.88 0.0449 3.42 0.04813.75 0.497 0.0859 7.73 0.0790 7.32 0.0676 3.79 0.0475 3.37 0.0514 3.690.745 0.0983 7.26 0.0917 6.87 0.0741 3.69 0.0508 3.32 0.0551 3.63 0.9940.1081 6.88 0.1011 6.50 0.0795 3.59 0.0543 3.27 0.0579 3.57 1.243 0.11556.56 0.1082 6.21 0.0840 3.51 0.0573 3.22 0.0605 3.51 1.491 0.1208 6.300.1137 5.97 0.0877 3.43 0.0598 3.17 0.0627 3.46 1.739 0.1249 6.08 0.11825.76 0.0906 3.37 0.0620 3.13 0.0646 3.41 1.986 0.1282 5.89 0.1217 5.580.0930 3.31 0.0639 3.09 0.0662 3.37 2.238 0.1306 5.72 0.1247 5.42 0.09503.25 0.0654 3.05 0.0676 3.34 2.486 0.1329 5.57 0.1272 5.28 0.0965 3.200.0667 3.02 0.0688 3.30 2.734 0.1345 5.44 0.1292 5.15 0.0979 3.16 0.06782.99 0.0696 3.27 2.982 0.1361 5.32 0.1310 5.03 0.0992 3.12 0.0687 2.960.0705 3.23 3.231 0.1375 5.20 0.1324 4.92 0.1000 3.08 0.0694 2.93 0.07133.20 3.482 0.1385 5.10 0.1338 4.82 0.1007 3.04 0.0699 2.91 0.0718 3.183.729 0.1396 5.00 0.1350 4.73 0.1013 3.01 0.0705 2.88 0.0723 3.15 3.9770.1406 4.91 0.1361 4.64 0.1020 2.97 0.0709 2.86 0.0726 3.12 4.225 0.14124.82 0.1368 4.56 0.1024 2.94 0.0713 2.84 0.0730 3.10 4.477 0.1418 4.740.1376 4.48 0.1028 2.91 0.0714 2.82 0.0732 3.08 4.725 0.1424 4.66 0.13854.41 0.1031 2.88 0.0718 2.80 0.0735 3.06 4.972 0.1430 4.59 0.1391 4.340.1033 2.86 0.0718 2.78 0.0736 3.03 5.469 0.1439 4.46 0.1400 4.21 0.10362.81 0.0722 2.74 0.0739 2.99 5.968 0.1444 4.33 0.1406 4.09 0.1040 2.760.0724 2.71 0.0741 2.96 6.464 0.1448 4.22 0.1412 3.98 0.1042 2.72 0.07242.68 0.0742 2.92 6.964 0.1453 4.11 0.1415 3.88 0.1041 2.68 0.0725 2.650.0742 2.89 7.460 0.1453 4.01 0.1416 3.78 0.1043 2.64 0.0728 2.62 0.07432.86 7.962 0.1455 3.92 0.1418 3.69 0.1043 2.60 0.0727 2.59 0.0741 2.828.458 0.1454 3.84 0.1419 3.61 0.1040 2.57 0.0727 2.57 0.0741 2.80 8.9580.1453 3.76 0.1416 3.53 0.1039 2.53 0.0726 2.54 0.0740 2.77 9.453 0.14523.69 0.1415 3.46 0.1036 2.50 0.0726 2.52 0.0737 2.74 9.950 0.1449 3.610.1412 3.39 0.1033 2.47 0.0723 2.49 0.0738 2.71 10.449 0.1448 3.550.1408 3.33 0.1031 2.44 0.0722 2.47 0.0736 2.69 10.946 0.1444 3.480.1405 3.27 0.1028 2.41 0.0721 2.45 0.0734 2.67 11.446 0.1440 3.420.1401 3.21 0.1026 2.39 0.0720 2.43 0.0733 2.64 11.943 0.1435 3.370.1397 3.16 0.1023 2.36 0.0717 2.41 0.0731 2.62 12.442 0.1433 3.310.1393 3.10 0.1020 2.34 0.0717 2.39 0.0730 2.60 12.940 0.1427 3.260.1390 3.06 0.1017 2.31 0.0715 2.37 0.0727 2.58 13.439 0.1422 3.210.1383 3.01 0.1013 2.29 0.0713 2.35 0.0726 2.56 13.933 0.1416 3.160.1377 2.96 0.1011 2.27 0.0712 2.33 0.0724 2.53 14.432 0.1415 3.120.1373 2.92 0.1008 2.24 0.0710 2.31 0.0722 2.51

TABLE 11b Results of strain sweep testing @ 60° C., Examples 46-50 46 4748 49 50 Strain (sample 36) (sample 37) (sample 38) (sample 39) (sample40) (%) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) tanδ G′ (MPa) 0.249 0.1046 5.72 0.0936 5.60 0.0872 3.36 0.0663 3.16 0.07023.18 0.497 0.1336 5.23 0.1176 5.20 0.0920 3.27 0.0706 3.10 0.0726 3.120.746 0.1584 4.81 0.1393 4.83 0.1000 3.18 0.0758 3.04 0.0769 3.07 0.9950.1769 4.48 0.1584 4.51 0.1096 3.09 0.0819 2.98 0.0810 3.02 1.243 0.19024.22 0.1705 4.27 0.1155 3.01 0.0857 2.92 0.0848 2.96 1.490 0.1999 4.010.1805 4.07 0.1197 2.94 0.0899 2.88 0.0890 2.92 1.741 0.2070 3.85 0.18803.90 0.1239 2.89 0.0922 2.84 0.0924 2.87 1.987 0.2124 3.70 0.1950 3.750.1286 2.83 0.0949 2.79 0.0945 2.83 2.238 0.2163 3.58 0.1990 3.63 0.13132.78 0.0972 2.76 0.0973 2.79 2.485 0.2191 3.47 0.2024 3.53 0.1333 2.740.0994 2.73 0.0997 2.75 2.736 0.2211 3.38 0.2055 3.43 0.1352 2.70 0.10102.70 0.1020 2.72 2.984 0.2224 3.30 0.2073 3.35 0.1370 2.66 0.1019 2.670.1038 2.69 3.234 0.2232 3.22 0.2090 3.27 0.1381 2.63 0.1030 2.65 0.10492.66 3.481 0.2235 3.15 0.2094 3.21 0.1391 2.60 0.1035 2.62 0.1069 2.633.732 0.2237 3.09 0.2101 3.15 0.1390 2.58 0.1041 2.60 0.1080 2.61 3.9780.2235 3.04 0.2111 3.09 0.1412 2.55 0.1048 2.58 0.1088 2.58 4.227 0.22322.99 0.2111 3.04 0.1408 2.52 0.1049 2.56 0.1100 2.56 4.479 0.2226 2.940.2099 2.99 0.1415 2.50 0.1051 2.55 0.1102 2.54 4.723 0.2219 2.90 0.20962.95 0.1416 2.48 0.1056 2.53 0.1115 2.52 4.972 0.2212 2.86 0.2101 2.910.1418 2.46 0.1045 2.51 0.1123 2.50 5.474 0.2194 2.78 0.2093 2.83 0.14142.42 0.1053 2.49 0.1127 2.46 5.970 0.2174 2.72 0.2072 2.77 0.1415 2.390.1054 2.46 0.1128 2.43 6.471 0.2153 2.66 0.2055 2.71 0.1415 2.36 0.10492.43 0.1135 2.40 6.965 0.2131 2.61 0.2025 2.66 0.1400 2.33 0.1041 2.410.1139 2.37 7.468 0.2109 2.56 0.2031 2.61 0.1396 2.30 0.1040 2.39 0.11302.34 7.964 0.2086 2.51 0.1988 2.57 0.1375 2.28 0.1031 2.37 0.1132 2.328.467 0.2066 2.47 0.1969 2.53 0.1383 2.26 0.1018 2.35 0.1130 2.30 8.9580.2045 2.44 0.1959 2.49 0.1369 2.24 0.1020 2.34 0.1125 2.28 9.457 0.20252.40 0.1943 2.46 0.1360 2.22 0.1014 2.32 0.1122 2.26 9.951 0.2004 2.370.1909 2.43 0.1346 2.20 0.1005 2.30 0.1126 2.24 10.451 0.1986 2.340.1896 2.39 0.1345 2.18 0.0989 2.29 0.1115 2.22 10.950 0.1966 2.310.1879 2.37 0.1340 2.17 0.0991 2.28 0.1105 2.20 11.446 0.1949 2.290.1859 2.34 0.1336 2.15 0.0970 2.27 0.1104 2.19 11.947 0.1933 2.260.1838 2.32 0.1321 2.14 0.0970 2.25 0.1098 2.17 12.452 0.1915 2.240.1825 2.29 0.1307 2.12 0.0964 2.24 0.1094 2.16 12.949 0.1900 2.220.1803 2.27 0.1298 2.11 0.0964 2.23 0.1088 2.15 13.441 0.1885 2.190.1796 2.25 0.1296 2.10 0.0957 2.22 0.1084 2.13 13.944 0.1869 2.170.1777 2.23 0.1278 2.08 0.0953 2.21 0.1079 2.12 14.435 0.1855 2.150.1764 2.21 0.1286 2.07 0.0947 2.20 0.1070 2.11

TABLE 12a Results (tan δ) of temperature sweep testing @ 2% strain,Examples 41-45 41 42 43 44 45 Temp. (sample (sample (sample (sample(sample (° C.) 36) 37) 38) 39) 40) −80.20 0.0187 0.0207 0.0201 0.02050.0324 −74.01 0.0185 0.0201 0.0199 0.0195 0.0243 −70.05 0.0191 0.02080.0209 0.0203 0.0234 −66.01 0.0209 0.0231 0.0230 0.0225 0.0245 −59.990.0308 0.0365 0.0373 0.0351 0.0345 −55.97 0.0502 0.0601 0.0608 0.05690.0547 −50.01 0.0829 0.0929 0.0829 0.0843 0.0848 −45.99 0.0901 0.10470.0950 0.1003 0.0987 −39.97 0.1239 0.1740 0.1882 0.1989 0.1851 −36.000.2060 0.3244 0.3500 0.3656 0.3425 −30.00 0.5200 0.7187 0.7458 0.74520.7535 −25.98 0.7445 0.7871 0.8235 0.8275 0.8960 −19.99 0.5936 0.52870.5819 0.6278 0.6999 −16.00 0.4247 0.3918 0.4339 0.4885 0.5450 −9.950.2718 0.2666 0.2951 0.3404 0.3766 −4.94 0.3203 0.3359 0.3527 0.37070.3752 0.07 0.2603 0.2796 0.2890 0.2958 0.2903 5.07 0.2203 0.2395 0.24430.2415 0.2300 10.04 0.1943 0.2120 0.2140 0.2029 0.1890 15.10 0.17670.1931 0.1931 0.1755 0.1605 20.10 0.1655 0.1801 0.1782 0.1551 0.140225.09 0.1569 0.1700 0.1665 0.1389 0.1252 30.01 0.1509 0.1622 0.15750.1258 0.1133 35.15 0.1457 0.1558 0.1503 0.1154 0.1036 40.07 0.14070.1492 0.1430 0.1058 0.0952 45.14 0.1351 0.1429 0.1357 0.0985 0.088350.10 0.1303 0.1375 0.1294 0.0916 0.0821 55.07 0.1265 0.1329 0.12370.0864 0.0774 60.12 0.1228 0.1290 0.1199 0.0828 0.0738 65.09 0.11920.1256 0.1161 0.0799 0.0710 70.10 0.1156 0.1220 0.1131 0.0771 0.068675.10 0.1128 0.1189 0.1101 0.0751 0.0661 80.06 0.1097 0.1160 0.10740.0735 0.0640 85.10 0.1072 0.1134 0.1046 0.0714 0.0623 90.13 0.10460.1109 0.1024 0.0699 0.0606 95.11 0.1026 0.1090 0.0997 0.0687 0.0590100.12 0.1002 0.1072 0.0974 0.0672 0.0579

TABLE 12b Results (tan δ) of temperature sweep testing @ 2% strain,Examples 46-50 46 47 48 49 50 Temp. (sample (sample (sample (sample(sample (° C.) 36) 37) 38) 39) 40) −78.44 0.0182 0.0187 0.0165 0.01590.0187 −74.09 0.0170 0.0165 0.0158 0.0154 0.0173 −70.14 0.0167 0.01640.0160 0.0158 0.0170 −64.26 0.0168 0.0169 0.0168 0.0164 0.0176 −60.660.0169 0.0177 0.0173 0.0171 0.0185 −56.74 0.0180 0.0190 0.0189 0.01860.0200 −50.59 0.0213 0.0240 0.0243 0.0244 0.0250 −44.91 0.0309 0.04280.0440 0.0487 0.0462 −40.68 0.0489 0.0921 0.0970 0.1099 0.1025 −35.000.1647 0.3453 0.3715 0.4101 0.3844 −30.72 0.3787 0.6395 0.6771 0.73640.7090 −24.91 0.7538 0.7431 0.8122 0.8955 0.9322 −19.25 0.6686 0.50470.5749 0.6696 0.7222 −14.94 0.5007 0.3779 0.4447 0.5288 0.5718 −11.060.3779 0.2922 0.3472 0.4211 0.4543 −9.02 0.3269 0.2580 0.3082 0.37070.4036 −3.77 0.4069 0.3582 0.3678 0.3744 0.3829 1.09 0.3381 0.30700.3021 0.2904 0.2900 5.75 0.2935 0.2723 0.2583 0.2352 0.2304 10.520.2640 0.2525 0.2308 0.2005 0.1932 15.45 0.2485 0.2409 0.2142 0.17760.1690 20.34 0.2398 0.2338 0.2027 0.1609 0.1535 25.38 0.2341 0.22980.1942 0.1505 0.1424 30.21 0.2303 0.2274 0.1892 0.1404 0.1342 35.170.2277 0.2247 0.1829 0.1323 0.1272 40.28 0.2241 0.2213 0.1767 0.12390.1203 45.51 0.2194 0.2154 0.1706 0.1173 0.1140 50.51 0.2133 0.20930.1642 0.1112 0.1088 55.07 0.2076 0.2038 0.1594 0.1063 0.1045 59.990.2034 0.1995 0.1550 0.1026 0.1011 64.91 0.2004 0.1954 0.1507 0.09860.0975 70.23 0.1954 0.1921 0.1477 0.0953 0.0950 75.01 0.1917 0.18870.1442 0.0926 0.0940 80.03 0.1890 0.1851 0.1414 0.0900 0.0899 85.190.1850 0.1815 0.1368 0.0878 0.0871 90.21 0.1807 0.1784 0.1343 0.08580.0852 95.18 0.1767 0.1735 0.1306 0.0830 0.0825

Tables 11a, 11b, 12a and 12b show that vulcanizates employing functionalinitiator-initiated SBR interpolymers exhibit significant reductions inhysteresis relative to compounds employing a n-BuLi initiated controlSBR and that this effect is enhanced when a functional group resultingfrom terminal functionalization also is present and/or the protectinggroups have been hydrolyzed to provide hydroxyl groups. Similar positivetrends can be seen in the G′ data in Tables 11a and 11b.

A more complete set of physical performance data was obtained onExamples 41, 43-44, 46 and 48-49. This data is summarized below in Table13.

TABLE 13 Compound and vulcanizate properties 41 43 44 46 48 49 syntheticpolymer (sample no.) 36 38 39 36 38 39 MDR2000 @ 171° C. (final) ML (kg· cm) 1.81 1.60 2.96 0.82 1.55 2.98 MH (kg · cm) 23.27 21.98 22.58 16.6418.05 18.24 t₉₀ (min) 7.32 4.82 4.29 5.88 6.72 8.16 ML₁₊₄ @ 100° C.(final) 17.0 33.3 88.1 21.3 45.2 104.0 Tensile @ 23° C. (final, unaged)M₅₀ (MPa) 1.84 1.44 1.40 1.74 1.52 1.62 M₃₀₀ (MPa) 11.86 13.80 15.4511.51 14.78 18.35 T_(b) (MPa) 12.0 17.2 17.1 18.0 21.1 21.2 E_(b) (%)328 341 332 471 387 358 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 1.711.45 1.48 1.36 1.45 1.53 M₂₀₀ (MPa) 6.43 7.25 6.69 5.90 7.66 8.82 T_(b)(MPa) 6.8 7.5 6.8 8.4 10.1 10.3 E_(b) (%) 196 201 183 278 270 225 Strainsweep (60° C., 10 Hz, final) G′ @ 5% strain (MPa) 4.502 2.855 2.7782.880 2.903 2.513 G″ @ 5% strain (MPa) 0.698 0.295 0.199 0.683 0.6100.263 tan δ 0.1550 0.1033 0.0718 0.2373 0.2099 0.1045 ΔG′ (MPa) 5.3041.617 1.091 3.939 1.279 0.956 Temp. sweep (2% strain, 10 Hz, final) G′ @0° C. (MPa) 14.930 10.029 8.704 15.808 11.632 8.390 G″ @ 0° C. (MPa)4.783 2.904 2.593 6.110 3.685 2.645 tan δ @ 0° C. (MPa) 0.3183 0.28950.2976 0.3844 0.3152 0.3127 G′ @ 60° C. (MPa) 7.391 5.511 5.082 6.0614.946 4.233 G″ @ 60° C. (MPa) 1.029 0.662 0.421 1.355 0.767 0.437 tan δ@ 60° C. (MPa) 0.1392 0.1199 0.0829 0.2236 0.1551 0.1031 Dynastat (60°C., final) tan δ 0.1161 0.0829 0.0553 0.2129 0.1285 0.0943 Bound rubber(%) 18.4 32.6 43.9 5.4 22.2 43.6

C. Examples 51-87 (Monomers)

Butadiene solutions (all in hexane), styrene solution (33% in hexane),hexane, n-butyllithium (n-BuLi, 1.60 M in hexane),2,2-bis(2′-tetrahydrofuryl)propane (1.6 M solution in hexane, storedover CaH₂), and BHT solution in hexane used in these examples were fromstock room inventory.

Commercially available reagents and starting materials included thefollowing, all of which were used without further purification unlessotherwise noted in a specific example:

-   -   from Sigma-Aldrich Co.—2,3-dihydroxybenzaldehyde (97%),        3,4-dihydroxybenzaldehyde (97%), 3,5-dihydroxybenzaldehyde        (98%), 2,5-dihydroxybenzaldehyde (98%),        3,4,5-trihydroxybenzaldehyde monohydrate (98%),        methyltriphenylphosphenium bromide (MTP-Br, 98%), ethyl acetate        (99.5%), and DMAP (99%), and    -   from ACROS Organics—tert-butyldimethylsilyl chloride (98%) and        TBAF (1 M in THF containing ˜5% water).

Column chromatography was conducted using 200-425 mesh silica gelsorbent (Fisher Scientific; Pittsburgh, Pa.). Thin layer chromatographywas performed on chromatography plates obtained from Sigma-Aldrich.

Testing was performed on vulcanizates made from rubber compoundsaccording to the formulations shown in Tables 9a and 9b (see above).

Example 51: Synthesis of 3,4-di(tert-butyldimethylsiloxy)styrene

To a stirred, cold (0° C.) solution of 23.2 g MTP-Br in 100 mL dried THFunder nitrogen was dropwise added 40.6 mL n-BuLi solution. After ˜15minutes, a solution of ˜22.3 g BTBDMSBA (from Example 35) in 30 mL THFwas dropwise added via syringe. The resulting yellow suspension wasstirred for ˜4 hours before being treated with NH₄Cl. This solution wasfiltered and concentrated under vacuum. The residue was purified bysilica gel column chromatography using 5% ethyl acetate in hexane as theeluting solvent, resulting in collection of 20.6 g (94% yield) of acolorless oil. ¹H and ¹³C NMR confirmed the compound to be3,4-di(tert-butyldimethylsiloxy)styrene (DTBDMSOS).

Example 52: SBR (Control)

To a N₂-purged reactor equipped with a stirrer was added 0.81 kg hexane,0.21 kg styrene solution, and 1.20 kg butadiene solution (22.6% inhexane). The reactor was charged with ˜1.9 mL n-BuLi solution followedby 0.55 mL 2,2-bis(2′-tetrahydrofuryl)propane solution. The reactorjacket was heated to 50° C. and, after ˜30 minutes, the batchtemperature peaked at ˜59° C.

After an additional ˜30 minutes, the polymer cement was dropped intoisopropanol containing BHT and drum dried. This polymer is designatedsample 52 in Table 14 below.

Examples 53-55: Interpolymers including3,4-di(tert-butyldimethylsiloxy)styrene Units

A series of polymerizations in a N₂-purged reactor similar to that fromExample 52 were conducted on mixtures including 0.81 kg hexane, 0.21 kgstyrene solution, and 1.20 kg butadiene solution (22.6% in hexane). Themixtures differed in the amounts of DTBDMSOS (1.0 M in hexane) andn-BuLi solution employed, specifically,

-   -   53—2.6 mL DTBDMSOS solution and 2.01 mL initiator,    -   54—9.2 mL DTBDMSOS solution and 1.92 mL initiator, and    -   55—14.3 mL DTBDMSOS solution and 1.80 mL initiator.        To each mixture also was added 0.55 mL        2,2-bis(2′-tetrahydrofuryl)propane solution. The reactor jacket        was heated to 50° C. for each, and the batch temperature peaked        at, respectively, ˜56° C. (after ˜32 minutes), ˜57° C. (after        ˜30 minutes), and ˜56° C. (after ˜30 minutes). Sufficient TBAF        solution was added so that the ratio of TBAF to DTBDMSOS for        each was ˜6:5, and these mixtures were agitated at room        temperature for ˜2 hours each.

Each of the polymer cements was dropped into isopropanol containing BHTand drum dried. These polymers are designated samples 53-55 in Table 14below.

TABLE 14 Polymer properties 52 53 54 55 M_(n) (kg/mol) 107 102 108 119M_(p) (kg/mol) 112 105 111 122 M_(w)/M_(n) 1.03 1.05 1.06 1.08 T_(g) (°C.) −32.5 −33.2 −31.5 −30.2 % coupling 1.41 3.05 4.90 7.10

Examples 56-58: Interpolymers Including3,4-di(tert-butyldimethylsiloxy)styrene block

To a N₂-purged reactor similar to that from Example 52 was added 1.55 kghexane, 0.41 kg styrene solution, and 2.52 kg butadiene solution (21.6%in hexane). The reactor was charged with ˜3.3 mL n-BuLi solutionfollowed by 1.1 mL 2,2-bis(2′-tetrahydrofuryl)propane solution. Thereactor jacket was heated to 50° C. and, after ˜30 minutes, the batchtemperature peaked at ˜63° C.

After an additional ˜30 minutes, portions of the polymer cement weredropped into glass bottles. Varying amounts of DTBDMSOS solution wereadded so as to provide, respectively, 1:1, 3:1 and 5:1 ratios ofDTBDMSOS to Li atoms. These mixtures were agitated for an additional ˜40minutes in a 50° C. water bath.

TBAF solution was added so that the ratio of TBAF to DTBDMSOS for eachwas ˜6:5, and these mixtures were agitated at room temperature for ˜2hours each.

Each of the polymer cements was dropped into isopropanol containing BHTand drum dried.

Example 59: Cold Flow Testing

Test samples were prepared and tested as described above.

Test results indicated that the sample prepared from the polymer ofExample 53 was nearly identical in cold flow performance to the sampleprepared from the polymer of Example 52, while samples prepared from thepolymers of Examples 54 and 56-58 all were significantly better (˜1.5×to ˜3.5× greater) than the sample prepared from the polymer of Example52, with the block interpolymers being better than the randominterpolymers.

Examples 60-67: Preparation and Testing of Vulcanizates

Using the formulations from Table 9a and 9b above, vulcanizableelastomeric compounds containing reinforcing fillers were prepared fromsamples 52-55. Those prepared from the Table 9a formulation aredenominated Examples 60-63 respectively, while those prepared from theTable 9b formulation are denominated Examples 64-67 respectively.Vulcanizates were prepared by curing these compounds for ˜15 minutes at171° C.

Strain sweep testing data is tabulated in Tables 15a (both G′ and tan δ)and 15b (tan δ only), while temperature sweep test results are tabulatedin Tables 16a and 16b.

TABLE 15a Results of strain sweep testing (60° C., 10 Hz), Examples60-63 60 61 62 63 Strain (sample 52) (sample 53) (sample 54) (sample 55)(%) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) tan δ G′ (MPa) 0.2490.0805 7.89 0.0868 7.28 0.0796 5.42 0.0714 5.32 0.497 0.0983 7.32 0.10666.70 0.0920 5.15 0.0808 5.11 0.746 0.1136 6.80 0.1232 6.21 0.1049 4.860.0914 4.89 0.994 0.1248 6.39 0.1348 5.82 0.1152 4.62 0.0998 4.70 1.2430.1331 6.07 0.1428 5.53 0.1227 4.43 0.1064 4.53 1.491 0.1395 5.80 0.14855.29 0.1287 4.27 0.1113 4.39 1.739 0.1446 5.57 0.1527 5.09 0.1330 4.130.1152 4.28 1.988 0.1486 5.38 0.1558 4.92 0.1365 4.01 0.1182 4.17 2.2370.1518 5.21 0.1580 4.78 0.1391 3.90 0.1204 4.08 2.486 0.1542 5.06 0.15974.65 0.1415 3.81 0.1223 3.99 2.735 0.1564 4.93 0.1609 4.53 0.1432 3.730.1240 3.92 2.984 0.1583 4.80 0.1618 4.43 0.1444 3.66 0.1250 3.85 3.2330.1597 4.69 0.1624 4.34 0.1457 3.59 0.1259 3.79 3.482 0.1609 4.59 0.16284.25 0.1465 3.52 0.1267 3.73 3.731 0.1621 4.49 0.1631 4.18 0.1471 3.470.1273 3.67 3.976 0.1629 4.40 0.1631 4.10 0.1479 3.41 0.1277 3.62 4.2250.1637 4.32 0.1630 4.04 0.1480 3.36 0.1279 3.58 4.474 0.1644 4.24 0.16293.97 0.1483 3.31 0.1280 3.53 4.723 0.1650 4.17 0.1628 3.92 0.1487 3.270.1282 3.49 4.973 0.1652 4.10 0.1627 3.86 0.1489 3.23 0.1283 3.45 5.4700.1660 3.97 0.1622 3.76 0.1490 3.15 0.1284 3.37 5.967 0.1665 3.86 0.16143.67 0.1490 3.07 0.1284 3.30 6.466 0.1666 3.75 0.1605 3.58 0.1490 3.010.1283 3.24 6.965 0.1667 3.65 0.1599 3.50 0.1488 2.95 0.1280 3.18 7.4650.1667 3.56 0.1591 3.43 0.1485 2.89 0.1277 3.12 7.958 0.1666 3.48 0.15833.36 0.1483 2.84 0.1273 3.06 8.458 0.1663 3.40 0.1573 3.30 0.1479 2.790.1270 3.01 8.955 0.1660 3.32 0.1565 3.24 0.1475 2.74 0.1264 2.97 9.4540.1656 3.26 0.1558 3.18 0.1470 2.69 0.1259 2.92 9.954 0.1654 3.19 0.15503.13 0.1465 2.65 0.1254 2.88 10.451 0.1648 3.13 0.1542 3.07 0.1460 2.610.1251 2.84 10.950 0.1643 3.07 0.1533 3.03 0.1455 2.57 0.1246 2.8011.445 0.1637 3.02 0.1527 2.98 0.1450 2.53 0.1240 2.76 11.943 0.16332.97 0.1520 2.93 0.1444 2.50 0.1235 2.72 12.441 0.1627 2.92 0.1512 2.890.1440 2.47 0.1230 2.69 12.940 0.1622 2.87 0.1505 2.85 0.1433 2.430.1224 2.66 13.437 0.1616 2.83 0.1497 2.81 0.1429 2.40 0.1220 2.6313.936 0.1611 2.78 0.1493 2.77 0.1424 2.37 0.1214 2.59 14.435 0.16042.74 0.1485 2.74 0.1418 2.35 0.1209 2.57

TABLE 15b tan δ, strain sweep (60° C., 10 Hz), Examples 64-67 Strain 6465 66 67 (%) (sample 52) (sample 53) (sample 54) (sample 55) 0.2490.1214 0.1169 0.1135 0.1012 0.497 0.1564 0.1460 0.1302 0.1063 0.7460.1856 0.1724 0.1466 0.1140 0.995 0.2070 0.1921 0.1599 0.1214 1.2430.2219 0.2057 0.1703 0.1275 1.492 0.2328 0.2154 0.1783 0.1330 1.7410.2406 0.2223 0.1840 0.1377 1.988 0.2462 0.2270 0.1886 0.1411 2.2380.2502 0.2302 0.1922 0.1442 2.486 0.2531 0.2322 0.1945 0.1467 2.7370.2550 0.2335 0.1965 0.1487 2.984 0.2561 0.2341 0.1978 0.1501 3.2340.2566 0.2341 0.1986 0.1514 3.481 0.2566 0.2336 0.1991 0.1525 3.7320.2567 0.2330 0.1997 0.1530 3.978 0.2561 0.2320 0.1996 0.1537 4.2300.2551 0.2309 0.1995 0.1540 4.477 0.2545 0.2298 0.1992 0.1545 4.7280.2534 0.2285 0.1990 0.1544 4.975 0.2521 0.2273 0.1985 0.1545 5.4740.2498 0.2244 0.1973 0.1543 5.970 0.2472 0.2218 0.1961 0.1539 6.4690.2447 0.2190 0.1942 0.1533 6.967 0.2421 0.2161 0.1929 0.1527 7.4640.2397 0.2136 0.1912 0.1518 7.964 0.2372 0.2112 0.1896 0.1512 8.4620.2345 0.2087 0.1878 0.1501 8.961 0.2319 0.2064 0.1864 0.1491 9.4600.2299 0.2043 0.1851 0.1483 9.958 0.2278 0.2022 0.1834 0.1475 10.4520.2254 0.2004 0.1821 0.1467 10.950 0.2233 0.1985 0.1807 0.1460 11.4490.2216 0.1968 0.1795 0.1451 11.948 0.2197 0.1949 0.1781 0.1442 12.4450.2180 0.1935 0.1771 0.1435 12.942 0.2161 0.1918 0.1759 0.1427 13.4410.2147 0.1906 0.1749 0.1420 13.939 0.2132 0.1892 0.1734 0.1413 14.4380.2116 0.1879 0.1726 0.1407

TABLE 16a tan δ, temperature sweep (5% strain, 10 Hz), Examples 60-63Temp. 60 61 62 63 (° C.) (sample 52) (sample 53) (sample 54) (sample 55)−77.92 0.0168 0.0226 0.0206 0.0230 −75.91 0.0165 0.0209 0.0195 0.0212−73.94 0.0166 0.0209 0.0191 0.0205 −71.98 0.0171 0.0209 0.0190 0.0200−69.80 0.0179 0.0211 0.0194 0.0203 −68.27 0.0189 0.0215 0.0205 0.0211−66.16 0.0210 0.0228 0.0223 0.0230 −64.04 0.0241 0.0249 0.0253 0.0260−62.31 0.0291 0.0289 0.0305 0.0312 −60.44 0.0368 0.0352 0.0379 0.0389−58.35 0.0467 0.0435 0.0473 0.0491 −56.51 0.0578 0.0533 0.0575 0.0597−54.48 0.0680 0.0628 0.0653 0.0679 −52.33 0.0743 0.0691 0.0687 0.0702−50.59 0.0768 0.0714 0.0682 0.0683 −48.66 0.0766 0.0718 0.0668 0.0657−46.40 0.0759 0.0724 0.0663 0.0639 −44.63 0.0761 0.0744 0.0675 0.0643−42.05 0.0782 0.0789 0.0714 0.0667 −40.61 0.0819 0.0860 0.0776 0.0719−36.56 0.1021 0.1158 0.1035 0.0932 −32.74 0.1559 0.1897 0.1642 0.1413−29.01 0.2822 0.3446 0.2897 0.2532 −24.84 0.5075 0.5866 0.5075 0.4396−21.01 0.7268 0.7533 0.7246 0.6818 −17.14 0.7282 0.6740 0.7437 0.7662−13.05 0.5616 0.4965 0.5906 0.6443 −9.04 0.4140 0.3637 0.4416 0.48681.41 0.3629 0.3188 0.3772 0.3918 10.85 0.2587 0.2308 0.2658 0.2667 20.290.2102 0.1906 0.2134 0.2060 30.48 0.1857 0.1710 0.1838 0.1729 40.670.1693 0.1591 0.1659 0.1522 50.36 0.1567 0.1476 0.1503 0.1353 60.340.1470 0.1378 0.1388 0.1229 70.43 0.1386 0.1300 0.1302 0.1141 80.160.1304 0.1240 0.1219 0.1066 90.55 0.1240 0.1172 0.1149 0.1005 99.960.1174 0.1111 0.1097 0.0947

TABLE 16b tan δ, temperature sweep (5% strain, 10 Hz), Examples 64-67Temp. 64 65 66 67 (° C.) (sample 52) (sample 53) (sample 54) (sample 55)−78.11 0.0210 0.0204 0.0194 0.0180 −75.94 0.0195 0.0189 0.0183 0.0168−73.97 0.0189 0.0181 0.0176 0.0163 −71.98 0.0185 0.0176 0.0174 0.0158−69.72 0.0183 0.0173 0.0170 0.0156 −67.90 0.0180 0.0172 0.0170 0.0155−66.24 0.0177 0.0169 0.0166 0.0154 −64.22 0.0176 0.0170 0.0166 0.0156−62.13 0.0175 0.0170 0.0165 0.0157 −60.44 0.0171 0.0166 0.0163 0.0158−58.48 0.0171 0.0167 0.0166 0.0158 −56.46 0.0171 0.0168 0.0165 0.0160−54.62 0.0171 0.0170 0.0169 0.0164 −52.44 0.0174 0.0176 0.0175 0.0168−50.59 0.0176 0.0182 0.0180 0.0174 −48.63 0.0186 0.0191 0.0188 0.0182−46.66 0.0198 0.0206 0.0201 0.0193 −44.53 0.0214 0.0226 0.0216 0.0211−42.57 0.0238 0.0258 0.0242 0.0231 −40.73 0.0275 0.0311 0.0276 0.0271−36.61 0.0426 0.0531 0.0429 0.0412 −32.98 0.0874 0.1185 0.0886 0.0827−29.09 0.2116 0.2851 0.2077 0.1959 −25.18 0.4444 0.5528 0.4449 0.4308−21.02 0.7131 0.7745 0.7227 0.7256 −17.23 0.7703 0.7406 0.7995 0.8779−13.28 0.6262 0.5718 0.6591 0.7666 −8.94 0.4651 0.4271 0.4986 0.59200.95 0.4466 0.4094 0.4368 0.4673 10.71 0.3291 0.3040 0.3022 0.3057 20.100.2834 0.2632 0.2481 0.2354 30.07 0.2673 0.2496 0.2281 0.2090 40.230.2572 0.2416 0.2153 0.1944 50.22 0.2474 0.2341 0.2050 0.1828 60.070.2373 0.2256 0.1959 0.1741 69.92 0.2274 0.2164 0.1869 0.1649 79.850.2192 0.2098 0.1791 0.1565 89.87 0.2119 0.2033 0.1705 0.1484 99.960.2025 0.1949 0.1605 0.1402

The data of Tables 15a and 15b (strain sweep at 60° C.) show that, interalia, the presence of B units results in a reduction of tan δ,indicative of reduced hysteresis. The data of Tables 16a and 16b showthat the presence of B units results in a general increase in peak tan δand tan δ at 0° C., indicative of, inter alia, improved cold and wettraction performance.

Example 68: Synthesis of 3,4,5-tri(tert-butyldimethylsiloxy)benzaldehyde

To a dried 250 mL flask including a magnetic stirring bar was added ˜5.0g 3,4,5-trihydroxybenzaldehyde, ˜0.3 g DMAP, 60 mL THF, and 10 mLtriethylamine, followed by syringe addition of a solution of ˜15.2 gtert-butyldimethylsilyl chloride in 30 mL THF. This mixture was allowedto stir (under nitrogen) at room temperature for about an hour. Solidwas filtered out of the mixture, and solvent was evaporated before thefiltrate was purified using silica gel column chromatography employing10% ethyl acetate in hexane as eluting solvent. A waxy product (15.3 g,96% yield) was obtained. ¹H and ¹³C NMR confirmed the compound to be3,4,5-tri(tert-butyldimethylsiloxy)benzaldehyde.

Example 69: Synthesis of 3,4,5-tri(tert-butyldimethylsiloxy)styrene

To a stirred, cold (0° C.) solution of ˜11.5 g MTP-Br in 100 mL driedTHF under nitrogen was dropwise added ˜19.5 mL n-BuLi solution. After˜10 minutes, a solution of 15.0 g of the product from Example 68 in 30mL THF was dropwise added via syringe. The resulting yellow suspensionwas stirred for ˜4 hours before being treated with NH₄Cl. This solutionwas filtered and concentrated under vacuum. The residue was purified bysilica gel column chromatography using 5% ethyl acetate in hexane as theeluting solvent, resulting in collection of ˜13.4 g (90% yield) of acolorless oil. ¹H and ¹³C NMR confirmed the compound to be3,4,5-tri(tert-butyldimethylsiloxy)styrene (TTBDMSOS).

Example 70: SBR (Control)

To a N₂-purged reactor equipped with a stirrer was added ˜1.55 kghexane, ˜0.41 kg styrene solution, and ˜2.52 kg butadiene solution(21.6% in hexane).

The reactor was charged with ˜3.0 mL n-BuLi solution (1.7 M) followed by1.10 mL 2,2-bis(2′-tetrahydrofuryl)propane solution. The reactor jacketwas heated to 50° C. and, after ˜34 minutes, the batch temperaturepeaked at ˜63° C.

After an additional ˜30 minutes, the polymer cement was dropped intoisopropanol containing BHT and drum dried. This polymer is designatedsample 70 in Table 17 below.

Examples 71-74: Interpolymers including3,4,5-tri(tert-butyldimethylsiloxy)styrene Units

A polymerization in a N₂-purged reactor similar to that from Example 70was performed. Other than the amount of initiator solution (˜2.9 mLhere), the amounts of materials added were identical to those fromExample 70. The reactor jacket was heated to 50° C. and, after ˜35minutes, the batch temperature peaked at ˜64° C.

After ˜30 additional minutes, 5 mL of a 1.0 M solution of the TTBDMSOS(1.0 M in hexane) was charged to the reactor; this mixture was stirredat 50° C. for ˜30 minutes before portions of the polymer cement weretransferred to glass bottles and terminated with

-   -   sample 71—isopropanol,    -   sample 72—SnCl₄, 0.25 M in hexane (using a 1:1 ratio of Sn to        Li),    -   sample 73—DMI, 1.0 M in toluene, and    -   sample 74—APMDEOS, 1.0 M in hexane.        Each sample was agitated for an additional ˜30 minutes in a        50° C. water bath.

Half of sample 71 was transferred to another bottle, and this isdesignated sample 71a below.

The protecting groups from samples 71a and 73-74 were hydrolyzed byreaction at room temperature for ˜60 minutes with TBAF solution (1Msolution in THF containing ˜5% water, using an amount so as to result ina TBAF-to-TTBDMSOS ratio of 11:10).

Each polymer cement was coagulated and dried as in Example 70.

TABLE 17 Polymer properties 70 71 71a 72 73 74 M_(n) (kg/mol) 128 141156 248 137 155 M_(p) (kg/mol) 133 140 140 461 140 140 M_(w)/M_(n) 1.031.07 1.21 1.46 1.63 1.22 T_(g) (° C.) −37.7 −36.1 −36.1 −36.8 −37.2−36.7 % coupling 0.58 9.12 24.7 69.2 49.6 24.4

Example 75: Cold Flow Testing

The polymers of Examples 70 and 73-74, as well as DMI- andAPMDEOS-terminated SBRs (i.e., no B units included in the polymerchain), were used to prepare test samples using the procedure set forthabove.

The test results indicated that the samples prepared from the polymersof Examples 73-74 both were better (˜2 mm thicker at any giventemperature) than a sample prepared from a similar polymer which did notinclude B units.

Examples 76-87: Preparation and Testing of Vulcanizates

Using the formulations from Table 9a and 9b above, vulcanizableelastomeric compounds containing reinforcing fillers were prepared fromsamples 70-74. Those prepared from the Table 9a formulation aredenominated Examples 76-81 respectively, while those prepared from theTable 9b formulation are denominated Examples 82-87 respectively.Vulcanizates were prepared by curing these compounds for ˜15 minutes at171° C.

Physical testing similar to that set forth above (i.e., tan δ versusboth % strain (at 60° C.) and temperature, both at 10 Hz) showed thatvulcanizates employing SBR interpolymers that designed to include one ormore B mer adjacent terminal functionalities exhibit significantreductions in hysteresis and other desirable properties in both carbonblack- and silica-containing vulcanizates.

A complete set of physical performance data was obtained and issummarized below in Tables 18 and 19.

TABLE 18 Compound and vulcanizate properties, silica compound 76 77 7879 80 81 synthetic polymer (sample no.) 70 71 71a 72 73 74 MDR2000 @171° C. (final) ML (kg · cm) 1.81 2.06 2.26 3.05 2.51 2.60 MH (kg · cm)23.11 24.50 23.63 24.36 22.72 21.90 t₉₀ (min) 7.52 6.64 5.00 6.51 5.295.29 ML₁₊₄ @ 100° C. (final) 19.4 23.7 34.7 44.3 47.3 47.3 Tensile @ 23°C. (final, unaged) M₅₀ (MPa) 1.81 1.92 1.98 1.88 2.03 1.85 M₂₀₀ (MPa)6.99 7.78 8.57 7.72 8.91 8.26 T_(b) (MPa) 11.1 13.3 12.9 11.0 11.5 11.1E_(b) (%) 288 301 272 262 243 248 Tensile @ 100° C. (final, unaged) M₅₀(MPa) 1.67 1.86 1.93 1.85 2.04 1.86 M₁₀₀ (MPa) 3.00 3.39 3.67 3.41 3.913.57 T_(b) (MPa) 6.3 5.9 7.1 5.9 5.9 6.8 E_(b) (%) 204 169 184 170 150180 Strain sweep (60° C., 10 Hz, final) G′ @ 5% strain (MPa) 3.913 4.0273.358 3.583 3.076 3.031 G″ @ 5% strain (MPa) 0.596 0.585 0.391 0.4460.265 0.277 tan δ 0.1523 0.1451 0.1165 0.1246 0.0863 0.0913 ΔG′ (MPa)4.319 4.266 2.411 3.007 1.283 1.406 Temp. sweep (2% strain, 10 Hz,final) G′ @ 0° C. (MPa) 16.912 15.208 13.477 13.513 11.173 9.577 G″ @ 0°C. (MPa) 5.545 4.951 4.729 4.642 4.154 3.629 tan δ @ 0° C. (MPa) 0.32560.3229 0.3477 0.3407 0.3678 0.3745 G′ @ 60° C. (MPa) 8.275 7.698 6.5526.612 5.577 4.768 G″ @ 60° C. (MPa) 1.164 0.945 0.750 0.751 0.532 0.396tan δ @ 60° C. (MPa) 0.1407 0.1227 0.1145 0.1136 0.0954 0.0831 Dynastat(60° C., final) tan δ 0.1218 0.1162 0.0925 0.1022 0.0702 0.0727 Boundrubber (%) 19.6 20.8 30.0 28.0 34.9 47.3

TABLE 19 Compound and vulcanizate properties, carbon black compound 8283 84 85 86 87 synthetic polymer (sample no.) 70 71 71a 72 73 74 MDR2000@ 171° C. (final) ML (kg · cm) 0.88 1.07 1.31 1.70 1.82 1.67 MH (kg ·cm) 17.14 17.13 17.32 16.24 15.93 16.66 t₉₀ (min) 6.80 7.39 9.28 7.029.19 8.47 ML₁₊₄ @ 100° C. (final) 23.0 29.3 41.5 49.7 55.3 50.9 Tensile@ 23° C. (final, unaged) M₅₀ (MPa) 1.37 1.37 1.34 1.24 1.21 1.21 M₃₀₀(MPa) 7.53 7.56 8.85 8.68 9.51 9.47 T_(b) (MPa) 15.2 12.3 13.3 18.0 13.615.0 E_(b) (%) 523 434 403 509 382 417 Tensile @ 100° C. (final, unaged)M₅₀ (MPa) 1.06 1.07 1.13 1.11 1.10 1.10 M₂₀₀ (MPa) 3.97 3.96 4.59 4.524.94 4.91 T_(b) (MPa) 8.0 8.5 6.5 7.9 5.2 7.8 E_(b) (%) 347 363 288 295209 273 Strain sweep (60° C., 10 Hz, final) G′ @ 5% strain (MPa) 3.0172.954 2.592 2.435 2.428 2.466 G″ @ 5% strain (MPa) 0.686 0.651 0.3970.341 0.256 0.295 tan δ 0.2275 0.2202 0.1533 0.1400 0.1053 0.1197 ΔG′(MPa) 3.832 3.550 1.549 1.182 0.668 0.916 Temp. sweep (2% strain, 10 Hz,final) G′ @ 0° C. (MPa) 15.112 14.778 12.050 11.149 7.742 9.731 G″ @ 0°C. (MPa) 5.989 6.272 5.042 4.927 3.489 4.251 tan δ @ 0° C. (MPa) 0.39600.4240 0.4177 0.4409 0.4505 0.4367 G′ @ 60° C. (MPa) 5.288 4.978 4.5524.004 3.048 3.798 G″ @ 60° C. (MPa) 1.144 1.138 0.780 0.673 0.379 0.533tan δ @ 60° C. (MPa) 0.2164 0.2286 0.1713 0.1682 0.1245 0.1402 Dynastat(60° C., final) tan δ 0.2134 0.2072 0.1406 0.1386 0.1052 0.1168 Boundrubber (%) 11.9 12.3 22.7 28.1 37.1 32.2

That which is claimed is:
 1. A compound useful for anionically initiating polymerization of ethylenically unsaturated monomers, said compound having the general formula R¹ZQM where M is an alkali metal atom; R¹ is a phenyl or polycyclic aromatic group having at least two OR² substituent groups, with each R² being a hydrolyzable protecting group which is nonreactive toward M; Z is a single bond or a substituted or unsubstituted acyclic alkylene, cyclic alkylene or arylene group; and Q is a group bonded to M through a N or Sn atom.
 2. The compound of claim 1 wherein Q is SnR⁷ ₂ where each R⁷ independently is a hydrocarbyl group or together, with the Sn atom, form a cyclic group.
 3. The compound of claim 1 wherein Q is NR⁸ where R⁸ is a hydrocarbyl group.
 4. The compound of claim 1 wherein said OR² substituent groups are on adjacent ring C atoms of said phenyl or polycyclic aromatic group.
 5. The compound of claim 4 wherein said OR² substituent groups are on adjacent ring C atoms of a phenyl group.
 6. The compound of claim 1 wherein each R² is a t-butyldimethyl-siloxyl group. 